the issue is that materialists and physicalists presume a different
question and answer that one instead.
I feel like the two parties are talking across each other.
They are all on the same page but they propose different solutions. Will any solution suffice, however? That is important.
Q1: Do dualists or other monists (consciousness, ideal) reply to
phenomenal descriptions of consciousness by saying, “Youre not
actually answering the hard problem.” ?
The hard problem only arises if you accept the gap between matter and mind. The Hard Problem is the artefact largely rooted in Cartesian dilemmas, as explained by Chalmers.
For a large majority of monists, there is no Hard Problem to start with and this is the solution.
The two common variants of monism are idealism and physicalism. The former says All is Mind, the latter All is Matter. The hard problem does not arise for monists who are reductionists; materialists such as Dennett, Papineau, or idealists like Kastrup. (There is also neutral monism, i.e. that of Donald Davidson or Baruch Spinoza, or that of panpsychism.)
Dualists and non-reductionists are the "gappists". They think there is seemingly an unsurpassable gap between the matter and mind and we cannot grasp how a pack of neurons can produce a mind. Those philosophers sometimes introduce another property of matter, or a whole new substance to account for consciousness.
The critique from monists–those who deny the gap–is that, if you have put yourself in this losing position where you make such a claim, then you can never make any progress. You made the gap mystical, ineffable and unsurpassable. You might never be able to answer the question, nor make any scientific progress towards it if you accept no solutions from the only ones which are available. D. Dennet, for instance, claims that we should proceed and only answer the "important" hard questions, which are also extremely hard but are the only questions we might meaningfully answer. Perhaps, he says, we should exhaust the existing possibilities and only then pose "magical" stuff (Churchlands, Dennett). The critique from idealist monists is also prevalent:
The hard problem of consciousness is not a problem that needs to be
solved, for it doesn’t exist in any objective sense. It is merely an
internal contradiction of the reasoning behind metaphysical
materialism, a conceptual short-circuit that arises as we logically
work out the implications of the materialist conception of matter. 1
In idealists' eyes, this is not a real problem.
Q2: Am I capturing what it is they are said to be missing?
Alternatively, the second question might even be, “Would philosophers
agree with, and even make, the distinctions I make?” about the hard
I have "pushed back" a little, as you see. Philosophers either do or don't accept the hard problem (but they all agree on its definition).
Dennett and others then proceed with ever more complex (and possibly
ever more accurate) physical models/descriptions of biological
functioning, mechanisms of the processing of perception, etc.
Dennet has most recently been saying we are like a trillion little
robots who “accomplish” consciousness:
Elsewhere he says “gives rise to”.
Not necessarily. Dennet doesn't just give more complex descriptions. Dennett tries to have a theory of consciousness having existing (however limited) resources. Other illusionist philosophers like K. Frankish, the Churchlands, or neuroscientists like Michael S.A. Graziano, Anil Seth also have different solutions and theories which try to explain the "hard question" (not a hard problem).
(Since you mentioned Dennett, he is essentially a first-wave identity theorist (Read: Introduction section from "Illusionism"), but those philosophers had to differentiate themselves from second-wave identity theorists that sometimes proposed additional quasi-states which are not directly observed via empirical sciences (Papineau).)
For Dennet, in his Multiple Draft model, mature consciousness is achieved through the brain implementing a so-called Joycean Virtual Machine, which is a specific operating system software in the brain that has the linguistic capacity. It implements and controls self-monitoring and self-narrative, essentially producing what we call self-consciousness. As you see this is a theory that hypothesises a concrete software-like faculty in the brain "giving rise" to consciousness. It does not propose additional ontological property aside from what we know from natural sciences.
However, no philosophical dualist (nor monist idealist) is arguing
that it cannot be “accomplished” by the trillion robots.
They do, of course, argue that it cannot be accomplished. For example, those philosophers use Searle's Chinese Nation and Chinese Room experiments against Dennett's claim. Those thought experiments were meant to invalidate "trillion robots claim".
Idealists also deny that "trillion robots" can achieve it. For idealists, it is completely the other way around than how Dennett has it. Mind is the ontological primitive. Your mind is projecting (representing) itself into the phenomenal world. It can be the intellect faculty that is projected (represented) as the prefrontal cortex or the emotional states (qualias) that are represented as your Endocrine system, and so forth. For monist idealists, Dennett's claim is backwards as the trillion neurons are just the pixels of your desktop screen through which you see everything. It is Mind that makes them, not the other way around.
Q3: Would addressing those numbered questions answer the problem? Is
that the kind of thing people say?
Since I think I answered your questions already I will ask another question, as an exercise of "pushing back".
The very question is, instead, whether any answer to the problem would satisfy a sceptic*? Is there any explanation that could eliminate the gap for sceptics? I doubt that. This is why reductionism will not succeed even if it is true that there is no gap because people would simply not accept these claims. That is an impossible situation.
*- i.e. Dualist or non-reductionist.