Hi S., You are having the same problems many moms are having today, Since this is your first and you probably will have more I want to give you advice for future kids, do things ealier, by the age of 2, bottles, breast feeding, pacifires, diapers and pull ups become more of habits than needs, the longer you do something the more natural and habit forming it becomes, my husband and I have raised 3 kids, and we thought way ahead and we looked at the bigger picture beyond the baby/tot stages, for example we never used pacifires, we only bottle fed, becasue you can get rid of the bottle, but you can't get rid of the breast, we introduced sippy cups to our babies as soon as they could sit up, they still got their bottles, but at one year when we took the bottles away, it was a smooth transition becasue they were already used to using a cup, for potty trainig, we started out first child (a son) at 20 months, by 21 months he was trained, by 2 he was using the toilet, our second child also a son, was trained at 19 months, he wanted to wear big boy underwear like his brother, so we told him you have to use the potty like your brother if you want to wear big boy underwear, and he did, our third child a daughter was trained by 22 months, and the only reason it was a later age for her, was becasue when we started my husband got orders for us to move to Japan, so with all that intelled to we decided to wait until we got over there to train her. One thing that we did S., when we started traing there were no more diapers, we used traing pants, not pull ups, a pull up is nothing less than a diaper without tapes, when you go from panites/underwear back to a pull up or diaper if is confusing to children, becasue they have always beem allowed to poop and pee in their diaper/pull up, so to have different results you have to do something different, pull ups are not traing pants, I don't care what the package says, they are made out of the same materials as diapers. If your little girl sits on the potty and sings, let her, she is not hurting anyone, she's not miss behaving, but you have to stick it out and let up after she goes, and not before, becasue like you said you take her off the potty and put a pull up on her, and that gives her the comfort and security to go potty on herself cause that is how she has always done it. Now you mentioned all's these things you have tried, the one thing that I see is missing, is discipline, coinsequiences for going on herself, all traing weather it's sports, diet, learning a new skill, all takes discipline, most children will do what ever they are allowed to do, simple as that, but they will think twice about things if there is coinsequiences for not doing what mom and dad are telling them to do. All the different things we have to train our kids through don't have to be battles, we didn't battle with our kids over anything, I know it's because of the way we did things, I'm not saying we are experts or that we know everything, a lot of what we did was the opposite of what we saw other parents doing that was not working, and we established from day one who the parents were and who the children were, and to this day, our kids are 25, 22, and almost 20 thanks us for raising them the way we did, and they tell us they are the men and women they are today because of the discipline and the way they we raised them, so we know what we did was the right way, for our kids, becaus the results are in.
Sorry for going on and on, You and your husband sound like very loving parents. Have you ever asked your parents how they potty trained you and how old you were when you were trained? just a thought. Wish you and your family the best. J.