Time to begin my campaign to review every ALeP card! Starting with Shire's Reckoning, we get the Minstrel Trait synergy. First, let's focus on her stats. Her 2 can be boosted to 3 with Let Us Sing Together, and this will let her not exhaust. If you wish to use Let Us Sing Together on another character, Light of Valinor works as well. Her 2 is not great when coupled with her 3 in isolation, but you have to look at her text box to consider her defense. Instruments coupled with Wooden Lyre can make her a brick wall in defense.
Her traits cannot be ignored. Noldor is a popular trait that has many toys, such as Light of Valinor. Minstrel is an ALeP trait, and it does not have as much synergy with Elena. However, Goldberry allows Elena to quest without exhausting if she gets a Song attachment.
Now, to look at Elena's text box. The cost reduction on Instruments is quite good, and it applies to every Instrument you play. Not just the first one each round... EVERY ONE! In a Forth, The Three Hunters! deck, the Restricted Instruments would be free (because of the contract's cost reduction), and that contract would be flipped quite soon. Her Setup ability is icing on the cake: allowing you to accelerate your symphony and choose which Instrument you would like to center around.
Lastly, let's take a look at her sphere. is a keystone sphere for Minstrels, and cards like Song of Slumber and An Unexpected Party can bolster Elena's potency. She also is eligible for cards like Ancestral Armor, but that can be expensive, and there are other ways to boost her .
All in all, a very strong hero despite her threat cost being higher than expected. Minstrel decks are quite fun, and Elena is a great part of it.