The racial restrictions are removed in v0.9.6 with the exception of Slimes (who will have their own unique breeding mechanic).
Viewing post in Aric's Expansion Rebred
How is testing going?
Waiting for update, as v0.9.5 is bit unplayable for my playstyle,
due most of the bugs mentioned in these posts on v0.9.5.
And your mod just adds to much good content to ignore.
For future:
I recently realized it is similar mechanic on cross-breeding compared to Strive 2 alpha game.
So having like a breeder trait from Strive 2 alpha would be awesome.
And you could apply also that partially to current MC breeders trait also.