Anyone Know About Tennissee Walker Horses?

Ok so heres the deal: my neighbor Seth bought a Tennissee Walker a few months ago. He’s my age I think. She’s a 3 year old filly. Solid black with really dark brown eyes. She doesnt have a name…Seth never named her. He keeps her in our other neighbor Mariahs pasture with Mariahs 3 horses. The people he got her from didnt take good care of her at all. Because of this, her growth was stunted (which wouldnt be a problem for me, because I’m a small kid). Instead of looking 3, she looks like she’s maybe 1 and a half. Seth took care of her for a while, but now he’s not. She also has worms and he has the medicine. He’s just not giving it to her. Mariahs parents bought it for him and gave it to him to give to her. But he never gave it to her. Mariah says she’s looking worse and worse. Mariahs parents have told Seth either take care of her or give her away. That or theyll give her away for him.

So since he’s done nothing, they asked if I want her. Mariah even offered to help me train her since she’s not broke yet.

I dont have a pasture, but my other neighbors Bonnie and Jerry do. Theres a horse in their pasture I call mine, but theres not much to do with her. She’s an old quarter horse. I dont know her exact age, but she’s around 22. Pretty much just brush her and feed her is all I do. I help Jerry do her hooves sometimes too.

My parents have made sure I know how much of a change this will be. And I know itll be a huge change. Going from a low maintenance old mare to a high maintenance little filly. Plus the little girl would be even more work since the first owners before Seth put a bit in her mouth and jerked back on it way too hard. it broke her jaw in 2 places; one on each side of her mouth. So she has a hard time eating.

I have a few names for her in mind. I was thinking Flicka, Midnight, Belle, or Phantom. Which do you like, or do you have a different one in mind?
She has a good personality. She comes to Mariah faster than Mariahs horses do. She’ll test you, but she’s willing to learn. (I figured knowing her personality might help with the name)

Can someone give me an idea of what else would need to be done with her?