Oh crud...I think my story just got a whole lot more complicated lol

please forgive me if I've missed this question somewhere else in this post, but here goes -
a) do all planets
always form around stars or can they use other environmental conditions in space to form (ie gravitational effects from other things?)
b) If a planet has a colony, would that planet have to be near/er a sun?
c) Would terraforming (making a planets environment habitable) be possible on any type of planet (within reason) given the right technology, or would some physics/geoligical issues
always cause problems?
d) Travel between star systems takes a seriously long time. If a star system has more planets, would they (the planets) have to be further apart to reduce any catastrophies, or is there usually set minimum/maximum distances to keep them together, and does this greatly affect the time it takes to travel between them?
e) is there a limit on the number of planets that can orbit a star?
Thats it - I think. Again I hope I haven't re-issued any questions here, and they aren't too far off the mark?
Thanks

Seraph.