Hey, sorry for the delay.
As for openvt: I'll check that this evening when I get home. Shouldn't Retrosmc pull it as a dependency, though? Since it's clearly not part of OSMC, because I would have it then. (Or maybe Retrosmc tries to install it, but fails somehow, during the installation).
As for starting
/home/osmc/RetroPie/scripts/retropie.sh directly from ssh: I tried that then and also had no luck, but it was giving me a different error. I don't remember what exactly, wish I had wrote it down. Will try that this evening, too, and get back to you.
Yes, it's a fresh 2017.02-2 OSMC installation. And like I mentioned before - it's the same whether I try it on my Pi 1 or my Pi 2 (and tried it multiple times).
If it helps, I could record a short video demonstrating the whole process, so you can see for yourself and maybe spot something that I'm not seeing/something I'm doing wrong.
I'm desperate to get it to work - switching cards between my OSMC and RetroPie is kind of a pain :).