MASTERMIND
1. Can you MM off poison/energy explosion damage?
2. Can you MM Earthquake damage?

EARTHQUAKE
1. Can you reroll Impervious if you roll a 2 or 3 for Earthquake during your turn?

Yes. Any damage, including BFC Earthquake damage, Mystics, etc can be Masterminded away to someone else.

Yup. Damage is damage.

Since the rule is 'once on your turn' the answer is yes. An interesting and nice 'loophole'. And here I thought the only way was if you hit your own figs with EE splash damage (obviously multi-splash damage).

Makes playing Earthquake a little less dangerous for some figs...