This may of changed, but when steam first came out you needed a steam id toplay on the LAN, which of course is nuts. Better take this to another forum for an answer. The steam forum may be best, or post in
here.
As for the other problem of spectating bots, have you tried running your server without mean and adding bots manually? My guess is that mean is not the source of the problem, and that the bots simply won't join until the round ends and a new one starts.