I want to believe that the beforus trolls are a mixture of the post scratch trolls and I want to know who got mixed with who

Again, there’s no defined mixes. I don’t think that’s not how Troll Genetics works, they just dump all of the genetic material together into a Prospit and Derse slurry, and the things that predominate on each Dancestor are traits from the Troll of the same caste- Aradia for Damara, Sollux for Mituna and such.