Thanks for the pointer; Universe Sandbox looks like an interesting tool. (No demo/trail period, it looks like, though it’s only $25.)
I really like the idea of a planet orbiting one but not both stars in a binary system, so I can get the variable lighting over the course of the year, as opposed to having it orbit the pair of stars. I’m also open to fudging how Earth-like the planet is; I figure I already know what life that can support, so it’s a good starting point, but an alien world should also feel, well, alien. I’m not sure what chaos would result if I opened up all the variables at once, though. :-)
I can tell I have a lot to learn about the relevant sciences, though!