Yes, the one on the left in the first picture is Chaetodon auriga or Auriga/Threadfin butterflyfish. They are beautiful and one of the most hardy butterflyfish, though still not really a beginner fish in my opinion.
Both of my butterflyfish are not reef-safe, as they will eat corals, but neither has proved problematic with my toadstool (Sarcophyton) soft corals. I will be testing these butterflyfish with some hardy "invasive" corals in my work tank in the near future, such as xenia, zoas, GSP, mushrooms, etc. that all could potentially be consumed by butterflyfish (hence one main reason I want easy "invasive" corals).
Small anemones are great food for butterflyfish, so they will definitely help keep you tank free of Aiptasia.
When I added the ocean live rock to my work tank after the recent upgrade, I picked one of the pieces because it had a nice 3/8" lightbulb anemone that I liked. After adding it to the tank, I observed it moving to a nice prominently-viewable position before it disappeared... it dawned on me later that I prompted its demise putting it in a tank with a butterflyfish. Almost certainly, it was consumed by my Auriga butterflyfish.
In the future, I may be starting an intentional Aiptasia tank for butterflyfish food.
