I don't necessarily think it's such a bad idea, but hear me out, what about Splatoon Lagoon?
Right? When you think about it, it's one of the best ideas I've ever had really. You have the stage area for those Squid Sister concerts, wet play areas would fit into the region perfectly as is, and it's still a super cartoony IP but it also has that unique punk/urban Japanese setting that stands out.
Plus the name! Splatoon Lagoon. C'mon now, how can they not really?