This deck looks to fulfill the Fellowship contract as quickly as possible, using resource acceleration from each of the three heroes.
Ally selection was pretty easy - any unique ally with a solid statline and some conditional readying could do the trick. With so few characters, Valiant Determination is actually useful! I’m also a big fan of Elrohir and Elladan. With a +1 to all stats and both of them out, you’re looking at a couple of very beefy boys. If you’re going against a deck without any Orc enemies, you might consider replacing the elf lads with your preferred unique allies.
Attachments are pretty much there to make your existing stats better or to grant extra actions, not much in between. Steward can go on Denethor. Along with Livery and an Armored Destrier, he can tank any two enemies more-or-less indefinitely.
If your hand gets crowded with unique allies you can’t play, discard them to Arwen, then Drinking Song or Elven Light to get to more attachments!