Valve posted this related information to the mailing list today.
The last TF2 update should have fixed the last problems with the player count for replay and SourceTV. The player count, as shown on the server browser, will never include replay or SourceTV. As some have noted, the fact that replay and source TV are "players" is an implementation kludge, and this fact should not be visible outside of the server. Also, the maxplayers settings and visiblemaxplayers should not be incremented to have an extra slot for replay, they should only count regular players. We know that this is a change from previous behaviour, but it is how we want things to work going forward. In other words, you should use the same settings for the player counts, whether you have source TV and/or replay enabled. (Eventually you will be able to have the both at the same time.) For example, if you want to have a server with 24 human players, and one reserved secret slot for yourself, you will set maxplayers to 24 and visiblemaxplayers to 25. These values should apply whether replay is enabled or not.
Your server will still increase the player count to make room for the proxies.
We know the zombie player count problem still exists, but apparently it has decreased in frequency. We're still working on it.