Rather than layouts, you probably want to hide and unhide layers for the local peer.
Layouts will break object syncing - that is the host will attempt to sync objects regardless of the layout state of the peer I believe.
It is possible, but you'll probably end up with a custom syncing system in the end.
Alternatively, you can move the viewport of the local peer to an area not relevant to the main multiplayer game. This might work with layouts as well.