Well, MSharingan grade genjutsu are harder to say for sure. I believe it would work, it fits, it's a mental command. But I have discussed with Scorps, and not all of them do. Izanagi and Izanami, for example, do not get released by this, they are superior. As for lower MS grade genjutsu, like the tsukuyomi, I would say it does work, but I won't argue too much if it turns out it doesn't, in an official judging. Tsukuyomi bends time, and although, inside your mind, time passes normally, and, technically, the release is a mental command, then it should work, but who knows. I do think it does.
As for the myriad, yeah, it does have some restrictions, but it is so vast of usage that it makes up for it. I find that I use it quite a lot, and it bothers me that sharingan can see through it so easily, given it's low rank, something that doesn't bother me against other ninja, because it is good to have low cost genjutsu. But yeah, you can use other genjutsu on the target, but you can use other gen on other targets, including 2 more usages of this same technique, on 3 targets total. You can also have a clone or a summon do layered gen on the same target. Well, I don't know about clones, but summons for sure