I looked on the wiki but her skill set is not listed yet. I have no idea what weapons to give her and her effective level for then.

I've had a look in the GECK and they are as below:

Rose of Sharon Cassidy (aka Cass)
Melee Weapons
Guns
Sneak

Arcade Israel Gannon
Energy Weapons
Medicine
Melee Weapons

Craig Boone
Guns
Sneak
Melee Weapons

Lily
No class. Mutants have all skills assumed perhaps?

Raul Tejada
Guns
Repair
Science

Veronica
Science
Unarmed
Energy Weapons

hth

If you are on PC:
Turn so you have Cass on screen (works with any NPC).
Enter console command mode "~" KEY.
Leftclick her so her name and code appears on top of the screen.
Type getav and press enter -where skill is one you want to know.

here is list of commands:
getav xp
getav health
getav karma
getav actionpoints
getav critchance
getav strength
getav perception
getav endurance
getav charisma
getav intelligence
getav agility
getav luck
getav radresist
getav damageresist
getav fireresist
getav poisonresist
getav guns
getav energy
getav explosives
getav meleeweapons
getav unarmed

Thanks!
I'm wondering if Companions suffer from Str and gun skill reqs. like the PC or if they can use everything effectively.
Also if they use chems or items aside from stimpacks.. like antivenom?