OK. The bad news is your projector isn’t telling the world it can can’t handle YCC video and it can’t recognise limited range input. The good news is:
- We don’t care about RGB/YCC - vero is
still sending YCCfalling back to RGB and the projector is happy with that
2. Your projector can display full range video using either RGB or YCC (as I say many TVs don’t do YCC full range) You can therefore choose either - I recommend YCC as it avoids an extra conversion step in Vero. - The splitter isn’t affecting things for the projector (it may be for the TV but as you say that’s irrelevant)
I’m not sure what was going on with your first set of tests - the log showed you had limited range set.
The remaining problem - letterbox mattes being the wrong colour is down to Vero. I can reproduce that. I’m not sure why this has never been fixed but 99.9% of users are watching on TVs or projectors that accept ‘standard’ limited-range video so we don’t get many reports. I was supposed to be following up on one of those threads you found 
. The problem is fixed in the new version of OSMC we about to roll out but I’ll see if there’s a hack you can use in the meantime.