Hello,
Thanks for waiting. I think I'm going to present a few points in a certain order and see if they help.
1. Presenting an opponent at a bigger Scale than the trollbabe means that she cannot defeat it. So if the seven trolls are presented as a single foe, she cannot beat it. If she tries, and rolls, successfully, then the GM must narrate that success only at her Scale, and what happens at the bigger Scale is completely under the GM's control.
Player's conflict statement: "I fight them! I want to slay them!"
Roll: trollbabe wins.
GM narration: "You easily slay the first one to reach you. The others grab you, disarm you, and hold you captive. What do you do?"
2. When confronted by multiple foes (again, presuming this means the group is higher than the trollbabe's Scale), the player may name a subset as her opponent in order to fight at her Scale. But that still means the GM has full authority over what happens at the higher Scale and therefore would look a lot like #1 above. Remember, just because the player says, "I fight the first troll!" doesn't mean the other six stand there like dummies, waiting their turns. If she succeeds, OK, she beat a guy. But simultaneously, the others grab her, disarm her, and hold her captive.
Therefore my point is that saying, "I fight each one, at my Scale, in turn" is a non-viable tactic. This is not Dogs in the Vineyard. You do not exclude external forces from the fight in order to resolve it.
3. As pointed out earlier, it is often useful to see what the player really wants the trollbabe to do. Let's say that she wants to kill the chief of a tribe, and seven warriors stand in her way. In that case, it is perfectly viable for the player to say, "I kill the chief," as the goal. The rules allow that! The guards cannot stop it! This is very important - it's 100% different from ordinary role-playing strategic situations, in which putting those seven guys there would form a barrier to protect the chief. She can in fact try to kill the chief, seven guys or no seven guys, and since the life of a single NPC is at her Scale, that's what the roll is about.
Now, granted, again, the GM has this group of seven guys (higher than her Scale) there in the scene. So what they do to her is the GM's job (grab her, disarm her, capture her). But since the conflict was called and the goal is at her Scale, the chief's life is now in question - and the GM cannot stop that.
I hope that helps. Please let me know.
I haven't addressed every individual poster because that would be tedious and I think - or I hope - that this presentation will cover all the issues.
Best, Ron