Thanks a lot! So it kind of depends on several factors, but as a general rule for a purely optimized build (which isn't required in Strive, but always fun to do), Purebreeds are where to do for the highest total stat, Hybrids are better for more evenly distributed and generalized stats, and Ralph's special hybrids put a further unique spin on it with some unique traits and stat changes that really just depend on the hybrid itself. Some of the specials are stronger than purebreeds, some far weaker. The last type, Mutts, can actually turn out to be the strongest possible build if you can get a pretty even split over multiple genealogies and have fractional percentages of them all. That takes some careful breeding, however. The elemental side is a whole different level to that, of course.
There's a lot more bugs in this last version (though I believe most if not all of the reported bugs are resolved for this upcoming release) as we were reintegrating a massive mod on this mod that had just now been updated from the old game version before a lot of code was reworked. That tweak mod had a lot of conflicts with this mod that we had to resolve and the contributors did an awesome job with setting all of the major conflicts and alterations behind tweaks inside of the mod's settings file. However, though we each did a bugtest run, we figured with the scope of the merger, natural conflicts, and added systems that there would be bugs that cropped up between that release and this. Basically, bugs suck but it wasn't unexpected.
Regarding contributing, we'd love to have you! We have an awesome team working at their own pace on multiple different ideas and levels. If you have an idea to add in or just want to help bugfixing, hop in the discord listed on the front page and we'll be happy to work with you.