Ahh, it sounds like Pietro has a couple of little sister types, whether related or not. I'm afraid, after thinking about it, Pietro might tend to use people that are around them a lot in his complicated relationship with Wanda...like, pushing Wanda toward her friends when he's feeling annoyed with Wanda, trying to pull her away at other times...
But that doesn't mean he wouldn't have a real relationship with Lorna in her own right, too. I mean, I feel like Pietro is perpetually unfinished, so it's probably sort of variable how he'll react (everything is with Pietro), but it's probably not complicated like Wanda either, because Lorna seems pretty self-sufficient? But if she's always around, they've probably worked some stuff out. I think Pietro was quite tolerant of the crush, at the time, and has got to the point where he'd miss Lorna if she wasn't around. How do you feel about teasing? They might have developed a few things they do together, because I'm very sure Pietro likes rock climbing (even before I knew he'd have earth-related powers...) and you know, sharing the same powers has got to be interesting in some ways, even (especially?) if it's really just copying...
And yeah, I know what you mean about RP. It's always like that, isn't it?