Now that' would ideally be a dream come true if one can get all the above. I don't know why the Xbox doesn't play back standard MP4.
So as far as I can tell there are 2 options:
1. Use the Xbox profile, while this is specifically made for the xbox it should also work with other players since it is a MP4 file.
2. Use the MKV profile, it is gaining popularity across devices.
On playing back MKV on XBox and Media Extenders
Apart from Xbox all the other devices should be able to play back MP4 files. Stick with H.264 for best size/quality, I would increase the quality factory and keep resolution high and bitrate around 2K-4K to maintain the quality depending upon resolution
(720p to 1080p)