Just to follow up on the Xantech control panel question... no, no control panel is required. The MRAudio can be controlled either directly by the HAI panel via RS-232 or by the MLS computer via RS-232. Nothing other than the MRAudio is required. I believe all of the other audio matrix devices can be connected in the same maner.
I am one of the few that use the Xantech so you may want to check out all of the other choices. Cinemar doesn't really have a supported Xantech plugin, you would have to use the MLGeneric Device plugin. The reason I use the Xantech is because 1) very long history of high reliability, 2) integration partner with HAI (my core system), 3) 8 sources/8 zones compared to 6/6 for most other system, 4) 30 RMS/channel vs 15 RMS/Channel for most others, 5) impedance matching on all channels allows 4 speaker per zone on one channel pair for larger areas, 6) Zones 7 and 8 allow addition of a separate larger amp for areas like very large rooms or outdoors.
Lastly, there's a lot to be said for brand-continuity - having as many parts of the system from the same manufacturer. This eliminates most of the "buy it, try it, shelve it" expense since they have been designed and tested extensively to integrate. I choose HAI which I believe to be best in class for automation/security systems. Unfortunately for me, Cinemar's HAI plugin is junk and they don't have a legitimate Xantech plugin
so you may want to go ELK.
As for lighting, UPB works very well with HAI so that's where I went although I have Z-Wave and X10 still installed. Just my opinion, but z-wave seems to be geared toward the DIYers while zigbee seems to be where the serious players are headed. I wouldn't be surprised to see the final solution for wireless lighting be a zigbee solution but its not there yet.
You're at a confusing yet exciting stage of HA, enjoy it now. It becomes addicting, and expensive and very time consuming.