I think that if you released/moved a mummy out and placed it somewhere in your neighborhood, preferrably giving it traits like Brave and Daredevil first, they could turn out to be firefighters... Well, it's a possibility.
"Oh no my house is burning!" "It's ok, here comes the firefighter!" "Why is he walking so slowly?": Epic.
I don't think that any released/moved out sims (including the different lifestates) can become maids, pizza deliverers, social workers or repairmen, because these jobs don't really "exist" for playable sims. Not sure about butlers.