Oh, this is relatively straightforward to answer, at least from an experiential perspective - everybody can check these things themselves, and nobody seems to have much more to say on it, really, at least nothing that would convince people beyond general opinion-building or belief-systems.
Preliminary:
Obviously my decision-making skills and reasoning are capable of realizing that I am conscious now (you'll kind of just have to trust me on this one)
Actually I do not need to trust you on that. After all, I am perfectly capable of realizing that I am conscious now, but what do I care about some text that appeared on my screen? By all that I know, all I ever see and hear is just some hallucination injected into my brain, floating in a vat, and I am the only conscious thing that exists in the whole wide world.
Just kidding.
On to your main points.
What would happen if I suddenly lost consciousness?
This depends on whether you eventually regain consciousness.
If you lose consciousness forever, then from your perspective, nothing happens. You just stop. You likely are familiar with the experience of a deep, dreamless, unbroken sleep. If your brain works like mine, then that time is not part of your reality. It's simply not happening. It is exactly like if you lost consciousness during that time, since that is quite literally what it is.
When sleeping, it is clear that what not happens is our consciousness sitting around in blackness, waiting for senses to awaken again. We can imagine this nightmarish scenario (e.g., a victim of war who had all their senses shot away, nerves cut so they get literally zero sensual input; but the consciousness still being around and everything else keeps working). This is not our nightly experience.
An even more intense situation would be if you are in a coma, let's say an induced one, maybe for a planned OP. If everything goes as intended, then you are gone from one second to the other, and re-appear some (sometimes significantly long) time later.
There are unplanned, traumatic comas which are the same. For example, I had a car accident with sudden deceleration once, and bystanders tell me that I sat slumped behind the wheel for 10 minutes, and then just opened my eyes and got out of the car. From my perspective, i.e. from my consciousness'es perspective, I had the crash (squealing tires, big bang) and immediately opened the door to get out. People could have told me anything, there was no experience whatsoever to believe or disbelieve them about it.
Obviously someone might argue that just because we do not remember anything, that does not mean that consciousness was really inoperative at that time. That may be as it will, there is (almost by definition) no way for us to know any useful answer to that. A glimpse into this are dreams - often we are aware that we have dreamed vividly, but at the same time we cannot recall a single detail. Sometimes we dream and are able to remember. Sometimes we dream and are also consciousness about it (or at least we think so in hindsight, who knows). This could imply that consciousness can probably work on a scale between 0-100% (or, again, it could mean that this is not the case, but that memory is just borked - we cannot know, really).
assumption that it's possible to remove consciousness from a brain without damaging it beyond function, which is questionable
I have no reason to think that's questionable. Granting that we don't even know (in the least) what "consciousness" even is, and that there a great many entities on this planet which are alive but don't show particular signs of having "it" (whatever it is), it seems very plausible to me that a brain could work just fine without consciousness.
The dead giveaway here is that even when we meditate for years, there is never a point where we are conscious about how our brain works internally. We get immense insight into our mind (i.e., things like how thoughts, emotions, senses and so on and forth "feel"; how thoughts pop up on their own; how it is impossible to suppress thoughts consciously; and many other wild and fascinating effects), but not in the low-level working of the brain. We do not ever feel individual synapses firing. If we had no brain surgeons, we would never have spontaneously "felt" that our brain is made up of quite separate areas with sometimes quite distinct functions. So it seems easy for me to assume that the brain could just function fine without consciousness, as long as my body is being fed and watered sufficiently.
My understanding is that free will is not entirely real; it is not my consciousness that drives decision-making.
The jury is still out on all that, but I don't see how the one has anything to do with the other. Consciousness works just fine with (the illusion of) free will (i.e., there are many people who are absolutely sure of free will). But it also works perfectly for people who do not believe in free will (i.e., those that do not believe in free will). Like with so many other aspects of the matter, we have not found a way or argument to decide, while at the same time most people seem to have quite fixed opinions on it.
So does it goes to assume that it could also realize when it's not conscious? Would it be scared? I think that I, personally, would be scared. Would my brain share the same sentiment? Me and my brain agree on everything, so it seems it would be scared.
The working theory (at least as far as I'm concerned) is that consciousness is the only thing within the brain that's "noticing" anything at all - i.e., all senses, but also thoughts, feelings, emotions like being scared and such.
On the other hand, when people experience fear, this is definitely not just some weird thing going on in consciousness, but there are definitely chemical reactions to witness in the brain. We can also assume that fear is something that developed quite early in our predecessors, long before consciousness. That's why it is so hard for people to "handle" fear - our brain sometimes runs away with it, and we cannot get rid of it just by thinking real hard, or just by deciding that we don't want it (i.e., panic attacks, anxiety etc.).
So sure - I can imagine that a consciouss-free brain can still "run the fear protocol" based on whatever physical-chemical-audio-based input it receives. But if your consciousness were off, there would be nothing to take note of it. A doctor could measure it with electrodes, but they would not feel it either.
would my brain falsely believe it is still conscious?
There is no reason to believe that there is anything in your brain that can believe anything when you're not conscious. Obviously all input which your consciousness adds to whatever processes are going on will be gone, but this is totally normal for your brain - it happens every night when you sleep. Depending on how consciousness is implemented on the wetware - let's just assume it is wired in some significant part of your synapses - over time those connections may atrophy like muscles, but that would is obviously total speculation (just a thought experiment, nobody has the slightest idea), but it seems quite unlikely that your brain would notice.
Could it put its hand on a hot stovetop because there's no pain?
Sure, in a way. Sleep walking is a real thing. We can imagine that your consciousness is gone for good, but your body basically sleep walks. Actual, real sleep walkers do really bad things in practice (i.e., bad accidents can and certainly do happen).
But the pain would, if nothing except consciousness changes, still bring a reaction. Pain is, like fear, a very low-level thing that has been there long before consciousness arose. Even the smallest amoebae know "pain" of a sort - probably not that there is any "feeling" going on, but there is some injury-response built in. So in your case, your unconscious body could walk up to a hot stove, could accidently/randomly put its hand there, and then the usual pain response, which works in milliseconds and very much faster than you can realize, will pull it straight back. There would be nothing in your brain that then notes the pain. The pain would just be (in the form of electrochemical processes going on).
Oh, famously you can cut off a chicken's head, and it will walk around for some while. There you have it, your very literal p-zombie in action. (Though maybe not that useful, who knows how conscious chickens are with the head still attached...)
Finally, keep in mind that our body does an awful lot of things totally on its own, with not the tiniest bit of consciousness involved. All workings inside your cells, all quick reactions, your heart beat, the complete digestive and temperature regulation and a myriad of other processes big and small work all the time without you being conscious of them. And even when the scientists make you believe in them without the slightest doubt, your consciousness is not able to be aware of them, or influence them, try as it might.
Would it feel lonely without "me"?
Consciousness is defined as that thing that feels everything there is to feel, and to take notice of things. As far as we know, there is nothing else that "feels" anything. Lots of "sensors" and processes and automatic systems, but nothing else. There is nothing that is conscious about consciousness except consciousness itself. When consciousness is gone, there is nothing left that can do these things.
Oh and ... damn ... you used the word "me". This is just a huge further can of worms. There is a variant of insight meditation where you try to find the place inside your mind that is "me". Have fun spending a great long time looking.
The topic of consciousness has been done to death on this forum, I'm sure, but I hope this question provides a nice spin!
Actually, since the time I've been reading here, consciousness has not be brought up that often; I feel we talk more about religion these days. It is a nice spin to argue about it. It is also slightly futile since we know nothing about all of that. Nobody knows what consciousness is, even in the tiniest bit. Still, great fun, thanks!
