Nice to hear that there ate 8 planet solar systems. Besides binary there 3 and 4 star systems. One thing to remember is that these usually have a neutron star, or black hole at the center. It is also possible to have a white dwarf star in a solar system this is a good place for iron for alloys. There are both jovian and terran rogue planets, and a lot if them. The most comnon star is either a red dwarf, or binary information on the internet says both ways.
You have failed stars. Solar systems can capture planets. Planets can revolve around star, super novas, and black holes. Planets can have more than one moon. Besides terran proto planets, expelled jovian planets, failed stars (sub brown dwarfs) jovian moons big balls of ice with a rocky core can be a rogue planet. Some rogue plsnets can sustain life. Some planets revolve in the star.
