recently adopted sun conure

I recently rescued a female sun conure, ( they has her DNA sexed) . she is a beautiful bird, but the previously owners cut her tail! OMG who does this!
she does not know how to play, I put her on my hahns play orb and she just sits there. She say What! and kiss. she is a lover, she is very tame, anybody can hold her.
She is a screamer, and yes I know sun conures are loud.
My question is: will her tail feathers grow back? and is there a way I can train her to be a little less loud.
I feel so sorry for her that someone did that to her.

Yes to both questions, but I would get started right away, lest she instigate loud conure calling/screaming from the rest of your flock.....my patty was very loud when she joined us & I just started talking to her in a very low voice, one she had to shut up to listen to.....at the time, I had six suns, 4 of which I referred to as the gang of 4...they were siblings fro two succeeding clutches 6mo apart & were being diligently worked with because they'd been parent weaned & never handled, so the noise factor would have gotten me run out of the neighborhood, had we had any close neighbors.

Anyway, I just kept speaking very quietly whenever Heidi squawked & then everybody started shutting up to hear what I was saying.....it's not a quick fix & might not work at your house, but it worked for me.....it helped also, that everybody got a peanut kernel if they weren't squawking & squawkers didn't.....that may really have been the clincher though.....