Post humans could be adapted to these conditions pretty much by definition, since the central idea of "post humanism" is to use technology and biology to transcend our limitations.
Assuming that our far distant descendants are keen to settle on "Super Earths" rather than asteroids and comets in free space, there is no reason to suppose they will not tweak their genomes to thrive in these conditions. This won't be a trivial tweak, since bones and muscles need to be denser and stronger, the metabolic system will need to be adapted to provide more energy to the system without causing overheating of the core or brain (in fact, the metabolism might really be tweaked to run at a higher efficiency so the post human won't spend all their time eating). The other major tweak will be the respiratory system, to deal with the higher atmospheric pressure and different partial pressures of the various atmospheric gasses.
When you get right down to it, post humans will be adapted to every environment they choose to inhabit, so you will see various metabolic and physical tweaks, with various forms of technological augmentation added to the mix (my own feeling is post humans will spend most of the technological effort on the mind, nervous system and communications, leaving the biological augmentation for the "background activity" tasks they don't want to spend all their time thinking about). YMMV