Hack with town and dungeon map edits?

RotDS and FF6: T-Edition have map changes. T-Edition is the only one having tilesets modification (FF4 import) and has new maps for that. RotDS has smaller map edits but a new castle is being worked on as shown here: https://youtu.be/1Lqsy5a5-Co

I don't know which utility tsushiy used for T-Edition but RotDS use FF6LE Rogue CE. Maybe it would also be possible to edit maps and expand tilemap data with FF6Tools by editing the json definitions file first. There isn't much tilemap space to work with in vanilla game so that's why most hack have zero to little map modifications.