RoxyWomen's Minnow Slip on Sneaker Shoe

Are these actually zero drop barefoot shoes?

They fit perfectly right now, will they stretch a lot and then be too big?? I got an 8 but usually wear a 7.5

Is the inside of the shoe fabric, or a rubber/plastic/synthetic that will be sweaty if worn without socks?

Do these shoes have any kind of arch support?