From personal experience zombie escape and zombie mod on cs:go are not very popular even if the server is no-steam. but, that doesn't mean you can't run other popular mods. you can easily configure surf server on cs:go, pay you know who and within 1 hour you will have full server, and I'm not suggesting to close cs:s servers but to host in other games especially csgo. Also one more thing, no-steam cs:go players are mostly cheaters they come like waves so i wouldn't consider running shooting mods, deathmatch to be more specific.

Good luck with your clan man, and don't listen to these hypocrites