Hornball is common for vulwargs, therefore I spent about 10 in game days cross breeding them with vulwargs for this trait to come over. I didn't spend two IRL days running around the field and checking if one with hornball trait spawns
. I even got two with hornball trait, but they were futas, not females, and quest says it need to be female. So no dice there. I even crossbred these futa hornball bees with other bees, to make sure offspring is bee and not 50% chance of ending as a bee but so far no luck, only more futa hornball bees.
Similar with dragons, nympho dragons are rarity to occur "naturally". But nekos are almost all nyphos so I cross bred them and got few dragons with nympho trait. But again, on opposite side... they were female dragons and quest asks for futas. Rest of the story is the same as with bees. So far I haven't got winning combination because I can't actually influence it. It's all on luck of the draw.
I even tried saving before sleeping but every time I reload and go to next day same offspring gets born. So you can't "cheat" that way. It seems offspring race/trait combo gets set when neph gets pregnant.
I haven't played last few days because from exploring and trying combinations for fun I got stuck on this :/