I do love a good boat ride, but Star Wars (for me) doesn't seem like the right IP for it. I don't think I can recall seeing a character take a boat ride within a SW film. The closest I can think of is when the prisoners swam away from the prison in Andor.
As for fitting, you did a great job showing the size of the area, but if they want to keep walkways, they are removing at least a 1/3 of that show building. With the current orientation, you would be looking at a HM without the Seance scene, half of the hallway of doors, the Maintenace bay, the ballroom scene, the attic, and the first half of the graveyard. So, we would be left with an attraction that is the equivalent to the loading area, endless hallway, conservatory, half of the graveyard, and the Hitchhiking Ghosts. And they would still need to find room for the Maintenace bay, so probably no HHG.
Not terrible, but certainly is a much smaller attraction and not enough room for a boat ride beyond the scope of NRJ.