Question: Why did Erle try to kill himself?
Question: Was it the colony's idea to turn Bill into a werewolf or did Marsha choose to do it of her own free will? I think it's the former because nobody seems to be angry at Marsha for doing it.
Answer: I think they were purposely brought there to both join the colony. Marsha, who desired Bill, was impatient and bit him. As for not being mad at her, the Colony was slowly turning to her leadership, instead of the Doctor's compassion treatment.
Why would the colony want Bill and Karen to join them?
Question: This question applies to both this movie and Howling 4. Was there some kind of hypnosis involved that made the husbands of the protagonist want to stay in the communities after they were bitten by a werewolf?
Answer: Whether it be dog or wolf, the primal instincts take over. Every creature, in nature, has an urge to seek out their own kind. When the husbands were bitten, they are consumed with the desire to hunt, kill and mate.
Question: Why did Eddie Quist give Chris his rifle back before transforming? Is it because he wanted to die, or because he (wrongfully) thought the gun would have no effect on him?
Chosen answer: The reason Eddie gave Chris back his rifle before transforming was probably because he thought the gun was loaded with normal bullets. Regular bullets (at least in this movie) do not kill werewolves. This is shown in an earlier scene with Eddie and Karen White when he confronts her about the police raid in the porno theater. The police shoot him down and it was thought that Eddie was dead. However, later it is shown that Eddie had escaped from the morgue. Also, right before transforming, Eddie digs the bullet out of his head. It was likely that Eddie was taunting Chris by daring him to shoot him, thinking that the gun would have no effect on him. What Eddie didn't know was that Chris had loaded the rifle with silver bullets, which are deadly to werewolves. If you look closely, you can see the shock on Eddie's face when Chris shoots him in the throat.
Answer: He hated the way they were living. Acting human, hiding who they truly were, integrating into "normal" society. He wanted to be wild and free. When they were feared and worshiped.