On a side note: then this would be the first thing EVER that i failed to cluster (so far i clustered everything in Unix, Linux and Windows.. this includes IIS, even Filezilla servers are loadbalanced in our environments :P)
Most likely you followed the installation instructions for these services while refusing to follow them for ISPConfig
1) There is a difference between the mysql databases of the websites and the ispconfig mysql database. ISPConfigs goal is it to provide a load baanced setup for the "workload" e.g. websites, email, etc. The configuration panel itself is always a master/slave system, but the websites, mail accounts etc. can be configured as a cluster with two or more nodes.
2) See post #7. There is a difference between the ispconfig mysql database and the website databases. MySQL is used in ispconfig as a kind of local configuration cache which is mirrored inside of ispconfig. So it is a requirement for ispconfig that each instance runs its own mysql server.
3) Thats something different and does not indicate that the replication works. The steps to debug ispconfig are described in the manual and in several threads here in the forum.
4) Install it and you will see that it works. As I explained in #7, you can use your mysql cluster for the wesbite databases but not for the ispconfig system configuration database "dbispconfig". You can use any hostname for the local database, as long as it is not connected to another ispconfig instance like on your setup.
5) So to get this working. Remove your extra mirroring and then reinstall ispconfig on the slave server to use the mysql DB on localhost for its local DB and let it connect to the master DB as remote server.