DD is 2 years old and has her gtube since just after birth (they placed it at 3 weeks). Her soreness lasted about a week, maybe a week and a half, but it was manageable pain, I think. She'd only wince if you actually *pushed* on it. Tapping it or bumping it didn't seem to bother her.
The PEG never got pulled out, although I did accidentally tug on it pretty hard once.

She did get one minor infection when she was about 3 months, I *think* just before she got it switched to a mic-key. No big deal, cleared up with topical antibiotics.
The mic-key got pulled out quite a few times but it's no big deal to just pop it back in. Now that she has a mic-key GJ we're a lot more careful because it means a trip to radiology to get it placed again if it gets pulled out.
I've taken DD in the bath and pool, but never anywhere with chlorine, although I can't imagine that would be a problem. If anything, it might help keep the site cleaner.

It leaks a tiny bit, but not formula, just a bit of gooey ooze. We put a
cloth gtube pad around her site. I make them but if you google it you'll find places to buy them.
I don't know what developmental stage your DD is at, but she may like a
gtube baby. I made one for my son and he gets a kick out of taking care of a baby just like his sister.
So here's a funny story for you:
My friends all have little boys. So my son mostly plays with boys. When I had DD, she needed a tube of course. Then a met a lady who's DD had the same problems and she also has a tube. DS at that point knew 2 little girls with tubes (and all the boys did not have one). He was about 3, maybe 3 1/2 and one day out of the blue he said, "Mama, boys have penises and girls have feeding tubes".

Later, one of my friends had a little girl (happy and healthy) and when we went to meet her, he looked her all up and down and said, "Mama, where's her feeding tube?!"