A summoned Dremora is not a follower.
Your followers wont sabotage you if you give them specific instructions. You can direct their movement to ensure they don't set off traps and you can tell them to wait while you stealth recon an area. A lot of players use them as mules this way, but I prefer to direct Lydia to attack enemies while I take pictures.
Lydia is my favorite follower. She's good with both bow and sword & shield and her level cap is 50. she'll also use staves if you give them to her so she can play the role of psuedo-battlemage follower for you. However if you aren't playing on a PC then she is not a good follower because she has an encumbrance bug where everytime she leaves and rejoins you she creates a duplicate set of invisible inventory (her default armor, shield and bow). Eventually this can happen enough times to exceed her carrying capacity.