by cycloneVB
After a game tonight (6-players) we had an example this question applies to perfectly.One player had Lightning Armor (caveat for this comment, I don't have the game in front of me so I apologize if I miss the names by a bit). Basically it allows the possibility to damage the monster who just damaged you by get a one-time rollback at the attacker. The question could be important because in our case the attacking monster also rolled hearts. The attacker hit for 4 damage so the defender could have scored up to 4 hits back at the attacker...who had 3 or 4 life. In our case the defender didn't have a crazy roll so the question became moot.
However, it was a situation where order of resolution is important because if the attacker applied hearts first it was impossible then for the attacker to be killed. But if attacks are resolved before hearts, the attacker could have died.
Before the die roll we decided to go with the order the actions are listed on the right side summary of the first page (Vp, Energy, Attack, Heal) which means hearts are the last die resolved. I was unable to find anything that specified an order, but we all agreed that using the order on the right side of page 1 seemed fair.
Finally, I don't think you can break your dice apart and must resolve them as a group. This is backed up in a general since because when the ruled talk about resolving attacks or heals it discussed applying all the dice (it's sort of implicit though). And second, a lot of cards say when you attack (shrink ray, poison spit for example) the damage is applied. The rules under resolving die rolls call it "Attack" not "attacks" which implies one occurrence to me. Also in the rules for resolving attac it states that the monsters take one damage for each claw rolled. So that seems pretty clear to me that you attack once on your turn and use all dice for that action. Same applies to the wording of Heal.