AFAIK you just could place them at your tent/base to make them invisble to other players.
No, I'm sorry. But I doubt it will, it just raises the SPECIAL Stat, not the actual skill points IIRC.
just tested it. it does NOT increase skills.
Why do they shoot you? Mostly they appear in the triangle vault 13 - Junktown - Lost Hills Bunker (BoS Hideout)...