1) Is FQM v.1.13 compatible with Gold 1.78?
Yes. Any mod that is compatible with 1.67 is instantly compatible with 1.78.
2) Is there anything else I have to take care of when I set up a game for PBW (I already have Oleg's modification to avoid trouble with starting planets)?
If you use large (good) homeworlds, you have nothing to worry about, and can keep the medium moons. There are no other issues that I am aware of.
