I wore them all day today too. I was upstairs organizing and cleaning the bathroom and my feet hurt. I figured I am just going to have to go back to my sneaker if my feet were hurting just standing there. I decided to wait it out. I don't know how long it takes for them to mold to your foot, but I wore them out side a bit today and they are not so bad now. I am still not sure if I will like them to wear all day at Disney or not though. Also they ARE the ones made in China. maybe if they were made in Canada they would be better

. The 4yo's seem way to small. I guess I will have to send them back but I think the 8yo's are ok.
Here's my questions...Do the sneakers give you pain, too, and they just your best "bad option"? Why are you trying the Crocs Relief if the sneakers work? I just suspect that you don't think that the sneakers are going to work for you at Disney, so you are looking for a better option. If this is the case, sit back and read a story and, hopefully, learn from my mistakes (although this involves Crocs Reliefs, the moral of the story isn't that these are the solution).
You didn't mention when you are going to Disney, but, hopefully, you have a bit of time, three months or more (otherwise, you won't have enough time for my story to help!).
Here's my story...I walk 4 to 5 miles per day, 5 days per week. In March, 2007, I started having foot pain on one foot underneath my toes. I put up with it until August, when I tried some new walking shoes. They were mid to higher end New Balance shoes, and they were great! The foot pain disappeared.
However, about a month or two later, I started getting a different foot pain in the other foot in a different area (on top of my foot). This was about October, 2007, and our trip was in January, 2008. This foot pain was so bad that it would hurt the next morning while I was in bed (before I even put weight on it in the morning).
Well, I bought and returned about 12 pairs of shoes trying to find a pair that would be comfortable for Disney (zappos.com is fabulous with their free shipping/free return shipping!). I just thought that I could find shoes to solve my problem - like most people, I didn't want to resort to a doctor.
About three weeks before we left, I bought the Crocs Relief. I liked the footbeds, but I don't like how they slide around your feet (I actually prefer to wear socks with them, which isn't too ugly with jeans/pants).
About two weeks before we left, I went to the Walking Co. store, and they recommended some inserts and shoes (great store, great selection of higher end comfort shoes, btw, and very patient, but wrong recommendation of inserts
http://www.thewalkingcompany.com/). I wore them around the house for one weekend, and they were horrible. I returned them.
I finally called a podiatrist, but I couldn't get an appointment until the week after Disney.
So, I ended up wearing the Crocs Relief at Disney most of the time. They did rub a blister on the top of one foot, but I managed with Body Glide and bandages. I did wear some sandals (the only shoes that I had in my house that didn't hurt my feet), but at Disney with sweat, the friction on the bottom killed my feet. I think that I wore them two days, and I really did a number on my feet (not the foot pain, though). After that, it was Body Glide, socks, and the Crocs Relief.
So, after Disney, I went to the podiatrist. I was very impressed with her and her explanation of the foot mechanics and why I was having problems. She recommended some inserts. With the inserts, you wear them one hour on the first day, increasing slowly. Even with that, they really fatigued my feet. At the follow up three or four weeks later, the podiatrist assured me that the inserts would be fine after 6 weeks. She was right, and now my walking shoes with the inserts are the only thing that I can wear for any long period of time. (Now I just have to find some cute shoes that can accommodate inserts!)
The Crocs Relief still work, even if they weren't ideal at Disney. I went to Target yesterday in sandals with no inserts, had some foot pain, came home, and put on the Crocs which really did give relief. I also like them on the tiled kitchen floor if I'm cooking a lot (DH has the regular Crocs that he likes for the same purpose).
So, here's the moral of the story. If there aren't any shoes that work for you, go see a podiatrist (find someone who can give you a rec). Although it can take some time, you can find real relief!
Good luck!