Our therapist helped us with over correction. We took our son to the restroom on schedule and it decreased once he went in the toilet. Over correction/positive practice involved having him clean up and we told him that it goes in potty. Not in pants. He was trained quickly. We used a pull up over underwear at night and on transportation. We never had an accident at night and number 2 followed number one. After about 3 weeks we never had an accident except for an occasional GI issue. At first he did not know how to handle loose stools.

My son didnt get it till he was 7. Pooping in the tub your body is relaxed and not tense. She may be afraid of the toilet. We bought something he really wanted put it high in the bathroom where he could see it and had a sticker chart. After so many times peeing and pooping on the potty he got his reward. But we did the sticker reward for other things so he knew the concept. We also took a whole weekend. Charted every time he peed and pooped. Sat him on the potty with books and music. We entertain ed him with bubbles ect till he went. They usually go around the same time everyday.
As for the clothes. We had to use overalls for a long time but that doesnt help if you are potty training. If the school is helping with training have them put overalls in for the bus ride home with pull ups.

I have tried the cleaning up and what not and putting it in potty etc but I haven't tried the undied under pull ups! Going to try that one thank you

Also, if she wants her clothes off when she goes, that would be fine with me as long as they go back on after finishing. My typical 3 year old did that while training. It may be more comfortable for her.

It doesn't sound like bowel/bladder control is the issue if she can hold it in. Have you tried social stories? Make a book about where you potty and the steps involved in using the bathroom. Maybe she doesn't like having you in the bathroom...as you said she goes when you turn your back. Maybe allow her to use the potty without you.