My daughter, Ava, sounds a lot like yours in the potty training area. She is about the same age (she'll be 3 at the end of June). We tried everything you have - using panties instead of pull-ups (she goes in pull-ups just like diapers), using stickers, doing fun things while she's on her potty, etc. What finally seems to be working, and a lot of people may not agree with this, is a little treat every time she goes. She calls it "potty candy".
We keep a little dish of candy corns or those little conversation hearts on the bathroom counter, and when she successfully goes potty she gets one, and we also make a big deal out of it by clapping and jumping around and telling her she did a good job. Sometimes she gets so caught up in the after-potty excitement that she forgets about the candy.
She now will wear her panties all day and rarely has pee accidents. Poop is a different story, but she's finally getting the hang of that, too. She'll actually tell me now when she has to go, even if she's already started, instead of waiting till she makes a huge mess in her panties. She wears diapers only at night now and when we are running errands. Good luck! I know it's frustrating.