Life has limits...
Hi
Nice series that one. But all the critters are within biological limits. Mercury and the various moons most definitely are not. Mars is a maybe. Venus' upper atmosphere is another maybe.
Life needs a certain temperature range - especially eukaryotic life - and it most certainly needs to live in some medium of exchange, water or gas. Space-life and high temperature life can be imagined but there are no living models for such and plenty of reasons to doubt they're possible at all.
Adam