Spoilered responses to two of your things:
Spoiler
4 and 5.) Ghouls are actually in-lore pretty damn tough to kill, it's just poorly represented in the games. Though that doesn't excuse the sheer incompetence displayed by everybody Coop fights or how nerfed Power Armor is.
10.) Yes, she's from Vault 31, as confirmed in her convo with Norm. Everyone from Vault 31 is a Vault-Tec executive.