Head voice and vibrato

Hey! I have a question about head voice and a question about the vibrato techniques in the Beginner level 2 course:

I have been looking on YouTube for more advice about head voice, and I notice how when the male teachers demonstrate headvoice versus chest voice, it kind of just sounds like they are just singing higher for the head voice register, and it's hard for me to tell how exactly they changed their register. Like they often sound like they are staying in chest voice when they demonstrate chest voice and then head voice. Why is that? It seems a bit different from what I'm learning here. Is it because my head voice doesn't sound like that because mine isn't as strong as theirs? Also, is it normal to sound breathy in the beginning when trying to sing parts of songs in head voice? I'm trying to do that but I get a more breathy falsetto sound often when I approach headvoice. I'm a female singer by the way.

Concerning my questions about the techniques for getting your vibrato started, is it normal to have slight difficulty maintaining the shaking sound? I think out of all the exercises the crying voice feels easiest for me. The ghost wail I think I am okay at but not as good with. But I notice when I try to apply those techniques to open vowels like Camille said, it's hard to keep the shaking sound consistent and stable. Is that normal and will I get better overtime with that?

It's very normal for your head voice to be weak and breathy at the beginning of your training! The experienced singers you hear most likely have a strong, well-developed head voice - or they may even be using a head-dominant mix, which does contain some "chest voice" function and quality. 

And yes, it's completely normal for your vibrato to be inconsistent at this stage! It will become more stable and consistent as you practice.