idk More seriously: a4: The very interiors of planets are... extremely odd. A smaller core for a more massive planet may mean the core's more dense, and that's likely to make the core at least a little hotter, but I don't think this would. a9: Generally, habitable zones for close binaries are found by taking the luminosities of both stars- from there, simple worldbuilding tutorials like Artifexian's solar system videos should answer that question for you. b1: You should be able to get a brand of cyanobacteria that thrives in such conditions- even if you had to guess how cyanobacteria lived on early Earth to do it. b1b: Probably, eventually- barring catastrophic climactic change or a big solar flare? b2: ...Possibly. I don't recall, but I think sulfur dioxide is pretty sucky for clouds. b2b: If it was evolved for it. b3: Again, possibly. If I recall correctly, its lack of a magnetic field is integral to the loss of Mars' own atmosphere- if it's younger, or if you find a way to get its core running longer (higher mass is an easy solution), it'll probably be fine. b9: That probably involves complicated fluid dynamics calculations, but so long as the methane doesn't get messed up it should at least tip the temperature a little longer- though you certainly don't need to be above zero celsius to have liquid water, even if it's the same pressure as Earth's surface.