Recently, Taleworlds officially released its modding tools and they've made good strides in helping modders.
However, multiplayer modding support is currently still unknown. The modding tools allow for asset editing and map editing but dedicated servers and official multiplayer modding tools have not been made publicly available. Obviously, this means the progress on the mod will be slowed.
It's likely it will still be sometime before this tooling is released. For now we just have to be patient and wait.
Forums.taleworlds.com
Under "Multiplayer/Server-Client" you can see questions relating to multiplayer modding. These have been put forward to Taleworlds but have not been answered, not a great sign.
It looks like they want to support multilayer but on the map like single player instead of true open world. If this is true it's bull$&!@