Obviously an optional letter isn’t required so you are good.
Getting letters is difficult. You have to stay on people.
If it’s optional, as opposed to an optional essay, I think it’s fine if you don’t have - but of course it may depend on the school.
A Freshman one in theory isn’t as good. But it certainly won’t hurt.
Good luck. I doubt it will move the needle one way or another. If they want the student, not having an optional LOR, from a non-teacher no less, won’t matter IMHO.