I wrote some deliberately vague stuff on the wiki for the relevant sector pages, extrapolating from what we know about the larger region.
Basically:
The Vargr might have reached it, some of them -- adventurous types, explorers, etc., who can say? The Extents is too vast and chaotic for any reliable records on the matter.
The K'kree might have sent expeditions, but they're not going to let anyone else know, so again, who can say?
There might well be Droyne there... who can say?
As for the known Minor Races, the Wandering People and the Hhkar travel extensively in the general region, so maybe distant fleets of theirs are established over there, doing their own thing? The Droashav might have come from there originally, and maybe there are forgotten Faar colonies?
All entirely speculative.
As for native races, almost certainly there are some... but no-one knows anything...
(Basically, a way of saying, nothing has been established out-of-universe and we've not seen any evidence that anyone knows in-universe, either).
So far...