With the cabbage, the question is whether the caterpillar is down there in the center of the head. Holes in the outer leaves aren't a problem in themselves, but they signal the possibility of a problem you're not seeing.

Best thing to fight the Cabbage Loopers is called Bacilus thuringiensis aka Bt aka Garden Safe Bt Worm & Caterpliiar Killer. I get it at Lowe's; I would imagine just about any store with a decent garden center has it. This is my first year growing broccoli and I;m wondering about head formation, too. Good luck!
Edie