He doesn't need to get attacked by the guy just make him hostile so we can expect him to trash talk them to get him angry and it should be enough
I doubt it, if only because we JUST had that, last fight. The nervous nun is the more likely target, either making her scared or making her friendly. She doesn't look like she wants to be there.
I think if he can find a way to make her unable to heal without defeating her (thus copying her heal), it will be a big boon.
THAT SAID, what I think the final result will be, is ultimately copying the muscle guy. But not to buff himself. Instead, buffing Marl to 12.5x making her much stronger than the other guy with heal knocked out. This chapter started by noting that Marl was buffing him, meaning the skill can be used on companions, and I think that was foreshadowing. Mikigami is not strong enough for 10x to make a big difference, but Marl is strong enough for 12.5x to make a huge difference