After spending much too long researching, my conclusion is: likely not, but I know for certain it works with cards like
Charming Prince since you choose when they enter the battlefield, not on the stack. And
More or Less says “spells” not instant or sorcery.
So for me I think I would house rule it to be allowed since it makes it confusing to players that creatures work, but instant and sorcery spells don’t, but I’m sure there’s reasons for it
I’m also unclear now if
curtains’ call fizzles if there’s exactly two creatures on the battlefield and then I tell it to look for three. My thought is yes that works because the targets are checked to be legal twice, but it gets wonky because it’s like, “do you check for the original targets, or now based off of the text do you look for three?? And why should I care because I don’t even run any cards like that??”
These are deep philosophical questions that keep me up at night.