Last time I remember them doing an OST Plus was friggin FF9. And that was, go figure, the cutscene music. Plus extra, unused tracks. Nothing cut iirc. Don't know if they've done others since. I've certainly never heard of retail exclusive tracks, that sounds awful.It's certainly a practice I've become accustomed to with Square. As it stands I'm withholding on FFVII: Remake's soundtrack with the intention of buying an OST Plus down the line. Even then, there's a possibility that some things may still be cut or retailer exclusive.
Just going by past procedures, anything strictly cutscene related has the highest chance of getting chopped.
There really is no logic to cutting cutscene cues though. The composers put just as much effort into those as anything else, what possible purpose does it serve to exclude them?