6510 Galactic Standard Year: Hiigarans were exiled. 'My' Hiigarans find their way into this universe some years later thanks to a temporary jumphole. Since it closed again there's no way to have Taiidans or Vaygr to have followed.
A few hundred years later the Hiigarans in this sector developed to what they are today, say 6700~6800 GSY.
9625 Galactic Standard Year: Vaygr start invading stuff. Over 3000 years later. Now I guess one can debate about how long the Homeworld GSY lasts, but I am still sure the Vaygr would need to travel back in time to appear in this sector.
Besides, what are the odds of another fold in space delivering the Vaygr to this sector as well?
Discussions aside, I find that maintaining two big mods costs me enough energy as it is, and I am currently without energy to begin with.