I agree completely with everything you mentioned mscion.

Odds are though...the re-engineering of the human body most likely will be needed for here in the future...
due to the ruin this place will most likely be.
from all the issues ...and then some ...that you express...
atmospheric radiation...chemical and biological extremes of toxification...
the ability to breathe in an atmosphere that isn't oxygen based....

all that would necessitate changing everything down to the red and white blood cells...extreme invasive change of our dna ...

on top of that...
I would imagine that due to the fact such transformation of the species would need time...and that such planning would have to take in to account that what we "think" the way the planet will change...may not change the way we think it will...most likely the planet will be in a state of flux for some time ...perhaps millions of years...until equilibrium is reached...
Meaning ....that our planning will most likely result in failure..
we design people over time to withstand a heavily laden sulfuric atmosphere...
But the planet decides that it will be something else...
or decides that the atmosphere....for a period of time ...a few years...hundred...thousand years..that it will be sulfuric ...then change...

Then of course there is the issue of how such changes genetically will impact on our dna...

How such impact will affect our brains...
since ...fundamentally...the prime need of our brains is ...after all ....oxygen....
We would need to change that.
also our cell structure...our skin ...
pretty much everything would have to be changed...

and it is a guess ...what exact changes should be done to accommodate an altering environment.

Sure we could do all sorts of things instead...
wild...possibles..
download our brains into robots...
download the entire species into a "matrix" conception.

Still we would have to figure out how to get past the whole "corrosive atmosphere " issue...since all such options would really be negated .

Then of course...
along the road to this "brave new world"...
we would also have to re-engineer the human mind...
to cope with a dead world...
Since ... we are watching ...all the species... here...and now...
take their exit.
And since we are no different than any other species...
in that ..we need to interact with our environment...and the species in it..
we are in for a tough haul...
if we have nothing to interact with...

Not really fun thinking about....
none of it....

So yes mscion...
we need to fix this place...
and we need to start ....the day before tomorrow...