[hdmkv]

Tried @ricardopvz's ROM and it indeed makes Play2's UX much improved over stock UI. However, my HD audio no sounds issues have returned (no TrueHD/ATMOS, no DTS-MA/X). Starting to suspect my Play2 unit may be a lemon.

Are those issues in Kodi/WMP/SPMC?

Unfortunately yes, in Kodi beta 3 and both forks. With stock v1.3, HD audio was mostly working after doing a factory reset and re-doing the necessary settings (Android, Refresh Rate switcher, and Kodi).