Is there any way to make it so certain players (say they have a password) can join a public server and remove a non-password holding player if the server is full?

The mod is teamfortress or oztf would work too

just for joining server present "vip system". Belong to spectators that mean u can join to server even all spec slots is busy, but that does't help u kick other players except via some mod help. u can kick user via native server kick command, but u need server rcon pass. Since rcon pass is too powerfull thing, i'm not recommend that way. So if mod does't support some kick feature, then no way i know.

No idea about qw server cmds but i used to run a CS server for TP praccy and could allocate reserve slots for team members. Each member of the team had a wee cfg with an ID number when the server was sent that number it would activate the reserve slot and even if the server was full it would allow him in by kicking the lowest scoring player at that time.

Dunno if this could be implemented in qw tho.

yeah that's what I was looking for