My guys get very cranky when they molt. Even my sweet Kreacher is grunting at me and stamping his feet now that he's molting. I would think it does itch while they are molting. Dobby had patches of hair missing when molting. It's called "blowing coat". Just watch the skin. After a couple of days the pigment will darken, which shows that new fur is starting to come in. If the skin doesn't change after a few days, then there was a problem. Scared the heck out of me when I first saw it and did major research on it. It is common for some rabbits. He's the only one that really does it though, thankfully.
And regarding the line on the kits faces, I believe it's just the way the fur is while they grow? We watched the line around Fawkes nose travel up and turn into an X.
Line above his nose
Turned into "Mr X". Now that he's older it's gone.
I don't know anything about the product you bought. Wish I could help you on that.
Karen