you dont need to be unrooted to activate. Make sure that the phone is off of your account and not activated on any other account that would cause an issue. Ive activated different rooted droids on many different devices and no issues.
Id recomend having them try dialing *228>choose option 3(not mentioned in voice prompt)>input phone number wanted to be activated on>last 4 of account holders social or password on account> and thats all.