How reasonable are my solutions to the two problems above?
I mean most of the language you use in 1. and 2. is still active verbs. You're still arguing from a framework of free will. Like "she" wouldn't be deliberately acting, contemplating, making decisions, reflecting upon her decisions. Because in determinism "she" would never have existed in the first place. The concept of her, would only ever have made sense to an external observer who sees a body doing stuff and so projects attributes upon it.
But inside herself there wouldn't be a sense of a self. It would just be an organic computer or some sort of machine that simply interacts passively with it's environment. So knowledge about it wouldn't make "her" change, you'd just manipulate it's inputs and so maybe get a different result maybe get the same result.
Now you can argue "But what if the human consciousness is a result of a deterministic process". Like tons of different organs and organisms formed a Leviathan to do the macro-management and make decisions. And that "thing" actually makes decisions, processes things and reflects upon is inputs and generates algorithms on how to deal with nature and sets them into action by signalling the respective organs. And because of it's usefulness to the other organs, actually "thinks" of itself as an agent because not being an agent and able to run ones algorithms is detrimental and works against the inner workings which would deterministically act against that.
Then the question is: Will that be substantially different from a free will. Would the individual be able to tell the difference? And does it even matter to the individual?
Like seriously the most likely scenario is that the other person will simply laugh at you if you tell them that they are a human robot. For all intents and purposes they have no reason to believe you. I mean cogito ergo sum (I think therefor I am) has once been postulated as pretty much the most fundamental piece of knowledge and marks the foundation for all further knowledge, so whatever you come up with as an explanation for why I shouldn't exist can only be wrong. Because the rejection of ones own self is incomprehensible for one's own self. So if it makes literally no sense, why should you reasonably accept that conclusion rather than questioning the premises?
Like even if you think of dream or coma, then no, dream is the self interacting with itself (I'm still present in that) and coma isn't real for the self. Sure people might tell you that tons of time have passed while you were in deep dreamless sleep (I don't know how coma actually works), but for all intents and purposes they are probably just lying. I mean you can convince yourself that they aren't actually deliberately lying by idk looking at other people in coma, figuring out how recordings work and that people are not smart enough to fake them, but that still doesn't change the fact that for the self it's on/off situation with nothing in between so there is no concept of what the in between is like. It's almost impossible to comprehend that ("almost" only because I don't know if you couldn't enter a stage of insanity where it makes sense). So no the most likely reaction is to ignore it, reject it, get defensive because of what this act of dehumanization might entails and so on.
What you seem to be thinking of is not so much if you were actually a deterministic machine, but if someone erroneously told you that you are (or you think they are erroneous in that). Like if people told you they can't actually see you and you thought "Great! I'm invisible" and started fooling around with that idea until you get bored with it.
- as the society (the system of justice):
Well nothing really changes. If you can't comprehend the ways in which another things is acting you might as well assume it's a subject rather than an object. I mean seriously look at how people treat their computers or cars for that matter. They essentially assume a "personality" in things for which beyond any reasonable doubt know, that they are inanimate objects with a deterministic logic. But as they don't comprehend how it works and just observe inputs and outputs of it they still derive a way to interact with them.
So you could argue that we're doing it wrong, because we don't understand how humans work. But then again what has changed? I mean it's not like we aren't already trying to understand how humans work. Or that even if our actions are based on completely fallacious logic, still don't achieve at least some desirable outcome (for the people doing them, not necessarily for the people upon whom they are done). So similar to kicking your computer and seeing it work again, things might not work because of our narrative but despite of it. But again that isn't remotely new and doesn't change anything, does it?
So it's a question of whether you apply a reductionist perspective that tries to understand humans by it's parts and their interaction or whether you look at them in terms of a holistic approach and try to make sense of them as a blackbox and the sum of their interactions with their environment. Though both approaches are currently so shallow in their explanation of humans that it doesn't yet matter and we kinda apply both, aren't we. So regardless of the question of free will and determinism to which most are kinda agnostic ("it matters when it matters otherwise we don't know and don't care").
Also in terms of your statements on what that would entail. Well it could be that or it could be the complete opposite of that.
At first, not having free will may seem really horrible for our justice system. After all, no one can be held responsible for their actions. It is just the circumstances that led them to this point.
Even with free will many crimes are a result of their circumstances. Like yes it might be a choice between options, but being left with shitty options and no positive perspective (either because there is none or because you're not aware of it) is a result of your circumstances.
Not inculpating anyone for their actions can be a perfect idea! In our current standpoint, we tend to demonise the criminals and cage them like animals (e.g. solitary) and then reason since they had free will, something intrinsically evil about them caused them to do bad.
I mean determinism would really dehumanize and objectify the "other thing" and it could very well be "intrinsically evil" like something in their algorithm processes harmless information in a very wrong way. So reactions like "keep it away" and "kill it with fire" might be "rational", though not very thought through but rather simplistic and brutal.
Instead, if we accept they didn’t have a free will, we can concentrate on the causes of their actions like poverty, poor education or even psychological disorders.
Nothing stopping you from doing that regardless. And you seem to be aware that this is not conclusive that determinism will lead to more understanding and less punishment as you yourself argue for punishment because of it.
So yeah that's pretty much a non sequitur and you can be a good person or an asshole regardless of free will or determinism (at least what we currently think of that).
The problem that I see with determinism is that people are too easy to accept that for other people and thus treat them as tools and as expandable, but are almost incapable of accepting it for themselves so that this assumption often has nasty side effects.