There are some core things about the mythical creatures I wish Meyer would have given an actual explaination for:
1. Turning into bats
She could have explained it as bats are attracted to vampires, but she choose not to adress it at all.
2. Sleeping in a coffin
How about that having something to do with them faking their own death or something?
3. Lack of Fangs
An evolution over time to adapt.
Related to the fact vampires are considered to be connected to the devil.
They meet at the full-moon.
2. Their Anger Issues (yes, I know that some of the wolves have this)
It could have been explained as a reaction to the moons phases.
3. Pack- Mind
Evolved trait or even a gift from the spirits.