If an enemy monster rolls two attacks each with 1 or more p-die, and I had Power Sink would I get 1 or 2 p-die? I guess the basic question is do Reactions only occur once?
You should get 2 power dice
You'll get two power dice, provided both of your enemy monster's attacks targetted one of your allied figures. Reactions don't trigger unless an allied figure is attacked, so if your opponent rolls power dice in an attack against neutral buildings, you won't gain anything. If your opponent rolls one attack against a building and one against your unit/monster you'll gain 1.
You should, because it's an allied figure (it's the same reason you can't attack your own installations).
How about this... what if I have Power Sink and am attacked with Lightning Attack? Do I get p-dice for both attacks? They did both use p-dice... we've been playing it you get it for each part of the Lightning Attack, just want a confirmation...
Reactions go off once per attack sequence. If you gain another attack through a Trigger like Lightning Attack, any Reaction would go off if he second attack is successful.