Dear Dean,
once again, you present an intriguing and well-argued essay. The initial question you pose---about how far we can stretch Gödelian results---is something that sometimes raises some eyebrows, and in principle, with good reason: Gödel's theorems have a very precisely defined range of applicability, that of axiomatic systems with a certain expressive power. Hence, or so the reasoning often goes, their applicability to physics (or other domains) is ultimately a category mistake---physics might be done with mathematical tools, but does not reduce to pure math.
There's something both right and wrong about this. I think a better way of framing this debate is to recognize that Gödel's results are really one application of a deeper principle in the particular domain of axiomatic systems, that principle being exposed by Lawvere's fixed-point theorem. With this, one can legitimately speak about extending 'Gödelian' (or perhaps, 'Lawverian') reasoning to domains beyond axiomatic systems, and describe phenomena like undecidability, the uncountability of the real numbers, the paradoxes of Russell, Richard, Grelling-Nelson and others, even von Neumann's treatment of self-reproduction within the same framework (see the expository article by fellow FQXi-contestant Noson Yanofsky on this: https://arxiv.org/abs/math/0305282). (And well, by means of self-advertisement, maybe you'd like to take a look at my essay, where I aim to apply these notions to quantum mechanics.)
You don't explicitly make the connection, but I think (correct me if I'm wrong) your argument can be read as a reply to another common strategy to deny the importance of Gödelian reasoning to our quest of understanding the world. That strategy, in principle, consists in noting that while it may be impossible to derive all possible phenomena from a given theory, nothing prevents us from achieving knowledge of that theory---as an example, suppose we lived in a cellular automaton universe, such as the Game of Life. There would be phenomena which we never could predict, as the general question of whether certain configurations occur is undecidable; yet, we could know the 'theory of everything', the CA's updating rule.
Against this, or so I read you, you mount the pessimistic meta-induction: so long as we find new phenomena, the picture of the world we have is liable to change; since in the example above, we'll always find new phenomena, we'll never be able to settle on a stable picture of the world in that sense. (Or at least, we won't be able to do so and know it; we might be right by accident, I suppose.)
I also relate very deeply to your point that the very preconditions of our knowing anything imply our inability of knowing everything---the mere act of knowing, in introducing the split between knower and known, ensures that no knowledge can ever be exhaustive. I have come to some similar conclusions in another essay of mine (http://bit.ly/AIbuddhanature).
There are also some shades of Popper's argument that no system can engage in perfect self-prediction.
Finally, I also appreciate the pointer towards the origin of Laplacian determinism in Cicero---I was not aware of that connection.
Thus, thanks, again, for a very thought-provoking essay. Best of luck in the contest!
Cheers
Jochen