Multiple cPanel servers with a common MySQL Cluster

Hi all Five years ago I tried to use one MySQL cluster with multiple cPanel servers. The issues were with some databases that WHM creates during installation (eximstats, cphukld, modsec, leechprotect etc.) because of username conflicts. I am aware of that and I managed somehow to go around it, but it wasn't production stable so I decided to leave it. I am also aware of the fact that documentation clearly states I should not do it because of the issues I mentioned, but I also have read that some people are running it anyway. But it is extremely inefficient to have MySQL server on each WHM node or one MySQL instance per WHM node, so I need to go with MYSQL cluster for all cPanel servers. So, I want to bring up a Percona PXC Cluster with the ProxySQL as a front. My question is (and this is for the staff and others who actually made it work) - how to overcome database & username conflicts? Apart from those are there any other gotchas that I could encounter? Thanks :)