Well, not to beat you up, or to put too fine a point on it, I think there’s a big difference between “immortal” and “indissoluble” here!
How do you support your assertions here, in light of article 4 (of your citation from I.97)? After all, in discussing the effects of the tree of life, Thomas says, “the power of the tree of life could not go so far as to give the body the prerogative of living for an infinite time, but only for a definite time”. This seems very telling – it seems that it undercuts your assertion of “immortality” absolutely. After all, the tree of life itself wouldn’t have created a state of immortality – that is, of infinite life – but rather, just a means by which a life (long, but only of a definite period) might proceed.
With this distinction in place, then, it would seem that we need to be quite careful about an assertion of what “indissolubility” and “incorruptibility” means, in this context! It would seem that Aquinas is not talking about immortality, strictly considered, but rather, about how a body might be corrupted or dissolved. To say that humans originally were meant not to be corrupted or dissolved does not, in this analysis, mean that they were meant to be immortal…!