Correct. It should have one barring gene, regardless of whether it is male or female, so you will just have to wait until it grows enough to show its sex in the usual ways.
Among the smooth feathered ones, you are pretty much correct about not knowing which mothers they have.
If you find a chick that has two barring genes (lighter coloring), that one must be male, and must come from a Candy Corn hen not the Frizzle hen.
When they are older, if you find a male chick that has only one barring gene (looks darker, or sires a chick with no barring at all), that chick must be from the Frizzle hen. But that has to wait until the chicks are old enough to show male vs. female differences in the usual ways (comb, feathering, and so forth.)
Beard is caused by a dominant gene. That means a chicken with even one beard gene should show an actual beard.
The beard gene also makes wattles smaller. Sometimes chickens with a beard get it picked off by feather-pulling flockmates, but I think we can take the size of your rooster's wattles as a pretty good indicator that he is just beardless, not a chicken with a plucked-out beard.
I do not have personl experience sexing Polish chicks.
I'm fairly sure they cannot be wing sexed.
I do not know about the head feathering. Crest shape seems to be different in males than in females by the time they are adults, but I don't know what age that starts, and I haven't learned to recognize it in chicks at whatever age it does start to show.
