Luffy is perfect for just happy CR! He adores platonic affection and just wants all. the. friends! If you're cool with it, they can meet on a private thread or just randomly while walking around Kaisou! He never gets tired of exploring this place.

Cale would probably be great for her, because he comes off as stand offish at first but he's also constantly helping people he runs into. I'm down for them meeting because she needs a little help? He'll be thriving with the dark because he's finally being allowed to embrace his shadow powers, so he'll be really leaning into learning to use those and helping others. If nothing else, hopefully they can be friends because Cale needs more friends lol. But yeah, I'm down for them meeting however you think is best!