I dont believe that anything as dramatic as terraforming is practical or even possible.

I'd also like to add that the amount you'd need to terraphorm Mars you could just... do to Earth. I think a lot of the points you made are valid, but some of those questions are pretty hypothetical.

Idk, I think it'd be neat for humanity to go off planet and extrasolar. Even if it's not a priority, you can't really do that unless you're working towards it. Doesn't really matter to me regardless, I'll be long dead before it happens.