Do trolls actually all have ancestors, or is it just the main twelve that play Sgrub? I ask because I'm not certain if Sgrub sort of forced them to have ancestors through ectobiology or predestination.

All trolls are said to have ancestors, but not in the same sense as humans. A troll’s ancestor isn’t just the ones that provided the genetic material for them, if it was they’d have hundreds of ancestors each. A troll’s ancestor is the person who provided the majority of their genetics, usually by the time a troll’s descendant hatches they’ll have been dead for many many sweeps