OK, here's my take, and I have the most sensitive feet on the face of the earth.
The Caymans are a 'no go' for me. If you don't like tennis shoes chances are you are like me & won't like not having foot freedom.
I also HATE the little black piece that are on many Crocs, they rub the skin of my foot and I just loath them.
I wear 'socklets' with the maryjanes, Prima ballet flats, & my Celeste's. I HATE the feeling of my bare feet touching ANY shoe. I have worn socklets with these styles ALL day in Disney parks and NEVER felt them being slippery at all. If you buy the right socklets nobody will be able to see them either. Ask Jen or Val, I wore socklets with my Crocs the whole time on Girl Trip and I don't think they noticed unless I said something.
The Prima ballet flat & the Celeste don't really have any parts that would 'rub' your skin to give you blisters. I would suggest one of those styles, or the new "Audrey" style sold exclusively at Hallmark.
This is the Prima "Ballet Flat:"
http://images.bloomingdales.com/is/i...97890_fpx.tif?
Here is the canvas Celeste:
http://www.flamingice.com/Merchant2/...lesteBlack.jpg
The Halmark "Audrey"
http://i14.ebayimg.com/02/i/000/c0/c1/cd77_1.JPG
Also, if you prefer a more 'sandaly' style I would suggest the Athens or the Ithaca. Both styles lack that little black piece that often rubs or causes blisters.
I agree with Dana too that ANY shoe you plan on wearing in WDW should be tested around the 'hood before you pack
