I originally posted this in the discord but feel like it would be a good idea to post it here incase more people want to try it out by no means is it a bug free experience expect crashes.

using More Zombie Players mod on workshop:

Steam Workshop::More Zombie Players

all players need to have the mod installed
host loads in after enabling mod runs these three commands
change 5 to however many you want

party_maxplayers 5
com_maxclients 5
lobbyAdvertiseMaxPlayers 5

then tell everyone to join
currently only got it to work on shadows of evil havent tried anything else and one barrier roulette v2
Gobble Gums don't work and players 5 to 8 dont have revive waypoints