G.W.
I don't know about the teeth, but my son is tongue tied too. He is 7 years old now and ever since he was a baby doctors and dentists have been telling me to get his tongue clipped. My standard response has always been "As soon as I notice that he NEEDS it, I'll do it." He breastfed for 9 months (only stopping by my choice), has perfect speech, and he's lost 3 teeth on bottom and they are all straight so far. So, my advice is this: if your daughter is having a problem that is caused by the tongue-tying then I'd get it fixed. If not, why try to fix what ain't broken?
Oh, and as far as the teeth growing in, that just happened to my son and it just caused the baby tooth to get pushed out... I think it's pretty normal. But your concerns are valid because you're her mom, so you do what you feel comfortable with no matter what any of us say! Good Luck!!