Hello, sorry for the delay in replying! But that sounds good and light enough, yes! I did have this specific Idea (might help us to flesh out the interaction) — Phantom is currently in possession of one catlike plantnimal, and said critter might have gone to Vash's house OR bumped into Vash (aka also took a liking to Vash, likely so). Phantom would definitely look for the little guy, so he'd knock on Vash's house (now that his shadow manipulation ability could no longer allow him to sneak inside other people's property) or he'd be forced to talk to Vash. Either way, they will get to know each other.

What do you think?