
I have the same question too. In KML, Keith was also attacked twice but they did mention that Chase was attacked before he did and it was more violent. It was done by a member of a cult or something but it didn't really explain why they were attacking these dominant alphas. I don't remember Grayson being attacked though.

No, for that Josh had to bite him. An omega's bite is permanent, an alpha's bite can be overwritten by another alpha.
Chase didn't want to have sex, because he didn't like being driven by instinct/pheromones and no reals feelings. Also he hates that he can't really remember everything while in rut, so he is afraid that he hurts someone. And he has problems with omega pheromones. Probably a result of not releaseing pheromones.
Josh stopped sleeping around because of Pete, and who knows, probably losing his backside virginity had a lasting effect on him, because Josh was a womanzier before. Looks like the Miller siblings have a type, they go for (formerly) promiscuous partners.lol
Why does Chase suffer more than Keith even though they are both dominant alphas, but I think Keith is not as complicated as Chase, more about looking for his first love. Am I wrong?