We're talking about this over on the Disneyland forum, but the Tiana remake for Splash Mountain was hatched back in 2019 specifically for Disneyland where Splash Mountain sits right next to New Orleans Square. The Disneyland version will extend New Orleans Square's theme into the woodsy "bayou" that used to be Critter Country.
Whatever happens to the awkward placement of WDW's Splash Mountain in the middle of Frontierland will merely be leftovers from the Disneyland artistic vision this remake was originally created for.
I see what you're saying but Splash Mountain is already in an awkward position in the MK now, because how does Georgia currently fit next to Monument Valley Arizona Big Thunder? I really think were overthinking this! I'm sure the Imagineers are aware of this.