My youngest finished day training about a month ago. Night training he is getting there, but not so worried about it. It will come.
I, too, told him he had to be potty trained by Disney. I gave an incentive. Each time he told us he had to go potty and went, he got a sticker. We kept a calendar in his room at his height. I found some small bug stickers. Everytime he told us he had to go potty and he did, he got a sticker. He got to put it on the calendar. He could see how well he was doing each day. Each sticker was worth money to buy Disney dollars that he could spend at Disney. I did a quarter a sticker. We were given our kids some spending money anyway. But he did not know that. He was always excited to get a "buggie" sticker and put it on his calendar.
But I think it is important to note, that if he had to poopy, we would sit in there with him and read a book so he could take his time and not feel rushed. We had no problem helping him through the process. Now he will go the bathroom on his own. He just yells when he is done so that we can make sure he did a good job wiping. I think it is important to show patience while they are in the bathroom. Example, he liked to have his underwear and pants completely off. It can take time to remove such items since he wants to do it himself. He wants to put the seat on the toilet. When he is done, he wants to flush the toilet. He wants to wash his own hands etc. Going to the bathroom can take 10-15 minutes. To me, it is time worth spent.
I don't believe in waiting until they are ready. Around here to get into preschool, they have to be potty trained. I have talked to parents with kids who were not allowed in. Plus, diapers are expensive, especially the pull ups. I am sure I will be bashed for that belief. So be it.
He and my older son are still wanting to earn stickers for Disney, so if they do their chores like keeping their room clean, picking up their toys and putting their plates in the sink when they are doing eating (without being told), they can continue to get stickers.
Good Luck. Find something that motivates them. For mine it was getting to know they could purchase what they wanted at Disney (in their price range) that mom and dad could not say no too. We already knew they wanted to build a light saber, get legos, buy lots of good snacks etc.