After much staring at pics and head scratching, I’m gonna guess…maybe they’re not actually in the same world, even though they’re interacting?
It makes no logical sense for Belle to actually be on a beach if they dressed her in stiletto heels. They have her standing on boards, which they can edit out, but there’s no boards leading down to the wet sand, so I’d guess they’re not gonna show Belle actually walking down the beach in those heels. So it’d make more sense IMO if she just appears in that spot. We know that Belle is gonna be appearing in NL somehow, someway, in 302, so maybe something similar is happening again? Ariel’s collecting seashells on the beach in NL, and an apparition of Belle pops up.