I don’t see how the studio has anything to do with if the plot will be used or not...Again no, don't expect Nomura and his team to start using elements from Tangled the Series as the show was developed by Disney Television Animation and not Walt Disney Animation Studios which developed the movie Tangled (regardless if a few of the people from the film are involved in the TV series).
On top of that, I just can't envision coming back to the world and having the visuals of the world switch to the style of the TV series over the original movie, plus the difficulties on creating the characters that were introduced in the show (e.g. Cassandra, Varian, etc..) in the CGI style of the movie which would be very difficult, cause most of the characters introduced in the Television series have never had CG models.
Frankly, I don't think that Kingdom of Corona, Monstropolis and San Fransokyo will ever return for the next KH games including KH4 wjen compares to Toy Box and Arendelle which seem to be the ONLY KH3 Disney worlds returning to KH4.
And you are aware if they were to use the world again, they would not change the style at all? They would just give those characters a 3D model, which if they’ve done this with all other 2D characters, they can certainly do it here.
Im inclined to agree, I think the plot would work really well within KH, seems the potential is there, and even if it is somewhat a long shot, never say never