I wonder why your rp leader didn't want to come here and explain themselves but arr. If they just end up in the edge of the map, I believe they just forgot to add coordinates of where they should end up/arrive in the next map?
For your other issue, I don't have any ideas. I thought that all you see and work with in the mapmaker, will be the exact same thing as when you visit it from cape inside the game, unless you walk into another portal from the exports or something.
Multiple textures as in usage of a terrainmask arr?