Yes.
Yes and no.
Currently that’s how it works. But there’s nothing technical to prevent us from modifying which target index is being used and how much hit mass is consumed. This is more of a question that falls into the design space and the rules, decisions, and constraints set up there. But that is a spot I’m not 100% comfortable with making certain statements in.
Nevertheless, to give a hypothetical example: A blessing could to effectively ignore target index if a target is killed by a headshot, thereby “extending” the amount of damaged targets.
So first target gets damage as if it’s the first target, if it was killed by a headshot, that hit mass gets refunded and the second target gets damage as if it was the first target. If that target was also killed by a headshot, the third target in line will take damage as if it was the first target, etc.