Eve,
I've heard from many that bulletproofing is more effective on a helmet than, for example, on shoes. Is that correct?
Yes, skeletons are more likely to hit the head, I mean
No, that is not correct.
You can't get bullet proof on helmets in survival, or is my information out of date? You can be creative, but not survival
Nope.
It doesn't matter where a hit hits you.
A helmet also reduces damage if someone hits you on the feet.
Hit is hit. Damage is damage. Minecraft is not more precise.
Not out of date, just wrong. You can get bulletproof on every piece of armor - since enchantments have existed.