Same media different format

[TheDreadPirate]

The automatic merging of "versions" only applies to movies. So keep that in mind.

For this to work automatically, you need to name the folder and the files exactly the same prior to the version designator. This would include the year and any IDs you've included in the folder name. An example from my library.

Code:

It's a Wonderful Life (1946) [tmdbid-1585]/
├── It's A Wonderful Life (1946) [tmdbid-1585] - Black and White.mkv
└── It's A Wonderful Life (1946) [tmdbid-1585] - Colorized.mkv

I've never had any media with different extensions and different subtitle types like you've described. I'm assuming if you put the "version" in the file name for the .srt file it would only be available to the mp4 version. And the embedded subtitles in the MKV would only be available when playing that version.