Not multiplayer compatible due to mod-atan-ash
Sadly we have to skip this overhaul. Would have love to try it out!

More detailed:
33.032 Error ClientMultiplayerManager.cpp:1081: mod-atan-ash was registered for the following events when the map was saved but has not re-registered them as a result of loading: on_entity_died (ID 4)
33.032 Error ClientMultiplayerManager.cpp:86: MultiplayerManager failed: "" + multiplayer.script-event-mismatch + "
" + "
mod-atan-ash"
33.034 Info ClientMultiplayerManager.cpp:608: UpdateTick(3229) changing state from(ConnectedLoadingMap) to(Failed)
48.116 Info ClientMultiplayerManager.cpp:199: Quitting multiplayer connection.
48.116 Info ClientMultiplayerManager.cpp:608: UpdateTick(3229) changing state from(Failed) to(Disconnected)
48.116 Info ClientMultiplayerManager.cpp:217: Deleting active scenario (global = true).
48.184 Info UDPSocket.cpp:237: Closing socket
48.184 Info UDPSocket.cpp:267: Socket closed

seems to sometimes load the save on the non-host computer, but sometimes they cannot connect. Usually they cannot connect

Atan needs to additionally register on_entity_died with mp events.

script.on_event(
{
defines.events.on_load, <-- yes
defines.events.on_player_joined_game, <-- maybe
}

temp solution: save server, restart server, immediately pause server, let player join.

1.2.01 disables the on_entity_died scripting which will allow for MP compatibility.

edit: Closer inspection revealed on_configuration_changed is hooked ergo maps old and new will function correctly in MP.
Previously it was thought that hook was missing and only new maps would work.

Submitting a pull request to Atan.