I think it depends on the alliance- in my alliance we generally like for council to monitor the activity level of allies, offer advise on strategy and base design, donate a lot, and keep the chat entertaining, while also monitoring to make sure it is kept respectful and light hearted. Other alliances may not necessarily have expectations of council members. As council you can promote, demote, and kick out allies (but not the leader or other council members). You can also accept or decline requests to join the alliance if it is set to invite only. Council:ally ratio is also personal to the alliance. For the alliance I am in (Nations League), we have 4 council and 30 members (after cleaning out inactives). Right now, this serves us fine, and 2 of us are most active, monitoring the entire alliance. Some alliances may decide to split up monitoring of allies, for example, 1 council monitors 10 specific allies; but I think that just depends on how the alliance sees the role of their council.