Summons/Followers:
I could just blithely assume you know what to cast when, but there's no telling who will read this later, so here's some pointers: Flamey is good at low level, and you can savescum Faralda for her (look at it, cant call them "He") for a measly 30 gold. Also, she's highly mobile, but when she does get CFed, there's a good chance that she'll take a few with her in the death throes. Frosties are a good mid level tank, especially for blocking doors so they can't escape, or to give you a breather. Slow, though. Stormies excell at antidragon, and can do light tanking a la Frosty. If you wanta Tank, it's hard to come up with a better one than Sir Stompy the Dremora lord. In fact you pretty much have to make a better one, but with Twin Souls, you can have all three.
The best Chassis for a DiY Tank is Mjoll the Lioness. It's a tough thing just to get her, involving a Dwemer Ruin crawl, Steam centurion, and eventually, you should get rid of her Ducky. So worth it, though. Heavy Armor, 2H, and Immortal. Grab Grimsever before going to pick up Esbern, then the three of you should be able to clean out Forelhost. Not for you, Mjoll loves Rahgot, and then do The Cursed Tribe for a full suit of Orcish Armor, and the Fellhammer. Done, son. I've seen her mash a Dremora Lord flat, unbound, on the roof of the College of Winterhold, "No Match at all!" Just cast it, stood back, and watched. That was the build I used.
Mjoll, Stormy, and Stompy will win any fight for you. You can help out with your little bow if you like, but you don't really have to. I warn you, this is an extremely OP build. Side effects may include boredom, and rerolling a new character.