Well, Bullfrog Syndicate style!
Special one mission mode like BB1.
One player controls one soldier, selective 4-16 players map scaling with enemies.
Limited purchase of equipment, Laser Squad style.
Selectable missions - Laser Squad / selected XCom / BB1-BB2 could be used or recreated.
Can be implemented as “hot seat” easily, LAN and Internet via user hosting and client.
Not much, but can be interesting, if players keep the pace. Rick could be dead, if not careful.