Deleted my previous post as I finally got it into Surround mode.
The stability of the surround piano leaves much to be desired. Brought down (crashes) Cubase 9, Pro Tools Ultimate 2018.4, and Logic Pro X (latest).
Finally was able to use Ensemble Pro Surround to host and then start the plugin. This needs more testing and fixes as a plugin.
Also, the documentation (manual) needs to devote a section to surround. There's no screenshots or actual mention of how surround should look so no indication of when it is correctly loaded. It barely gets a passing mention. (For instance, there are 6 categories of Factory presets in surround vs 3 in stereo (even with the full library))