You don't need to use your realname. In fact it's more practical if your name on the server is the same as here in the forums.
With the autoupdater you can easily install all mod-tracks and mod-cars that are used on our server. Just install it, and let the updater do its work for an hour or maybe a bit longer depending on your internet connection and then you don't need to worry about having additional content installed.
It is possible to just install the track for example but it's simpler to just use the autoupdater. Has nothing to do with anti-cheat though.
Password should be posted in this thread or added in the first post right before the event starts. Maybe you even get a PN with the password. I think we tried it last time, not sure how it will be dealt with in Bathurst.
The problem is if the password is public people can join on "server 1" even though they havent signed up and they take away the car of a driver that signed up here. If the password is only distributed via PN some people might not show up and then the server is not full although there might be some drivers who'd like to join the server but didnt sign up in time (or who couldn't be sure if they can make the start).
Both versions are not ideal but that's how it is in Assetto...
So in summary, just look here in the forums and check your PNs, then you'll find the password for sure.
In theory you can join the server at any point during practice or quali as your signed up now. The earlier the better though because as I wrote above otherwise we can't be sure who might turn up late or might not turn up at all.