To remind, aeons ago there was an alliance of four highly advanced races. Three of them were prominently featured on the TV show, the fourth wasn't. The few hints of their existence were close to be worthless.
So what do we know?
- they are an ancient powerful race
- they are called Furlings
- ...and that's it.
Judging from the other great races, they could be anywhere, off in another galaxy, gone into some alternative dimension or a higher level of existence, or might just be on the next backward planet without anyone noticing. They are surely benevolent, or at least benign, but you know it's never that easy. So many options... and who but the Citadellians can find the most reasonable explanation?
Post away!