Good guess, but sorry, no. This riddle would probably apply equally to a number of people, so maybe I ought to add a hint.
Two who are similar,
I was the worst.
The other came second,
'Twas I who came first.
*thinks in twos...* Ummm... Polly maybe?
Thank you, Hobbit!
Nope, not her either.
Edmund?
Ooh, um... Bree?
Thank you, Hobbit!
No...
My surroundings were changed
In a moment's heartbeat.
There were others who followed
As I made my retreat.
Jadisssss???????
I wanna say Rishda, but the "others who followed" doesn't seem right. Or Emeth, but I'm not sure who he's be compared to that would make him "the worst".
Edit: or ginger?
No, sorry. (Yay, I made hard one! 
)
Blast it. And here I thought maybe I hit it after memorizing all three pieces. 🙂
😆
Uncle Andrew?
No...
Hint:
One who was under me
Stayed when I fled:
One quite unlike
The others I led.
The leader of the LB dwarves?
Nope.
