All righty, for the other noob like me: I managed to get a little bit further. The arcemu logon and the other thing fail at the password phase because they don't yet know the password you and I have chosen.
In the project anthrax repack map where the arcemu-world.Exe and other arcemu file are located is a map called configs. In that config map are both a logon and world config file that can be opened with wordpad. Both of them have several lines referring to a very simple password. Change those to your own password.
This gets the logonserver file to run to where I think it's supposed to be. It's in a state where it says "Success! ready for connections"
The world file runs up to where it says "[Arcemu] logoncommclient: connection failed. Will try again in 10 seconds."

If I delete the blizz downloader for the next patch in my wow directory, I can get all the way to the login screen without the game trying to patch, but once I've entered a login and password I found in the database it either tells me to restart wow because a patch needs to be downloaded, that the login server is down, or that it can't connect.