Where are they manufactured?

Tag says China which explains having to get size 2xx rather than size 8 or 9. But they are thick, soft cotton. Very comfortable. Not sexy, but i'm 65 and chubby so who cares?

My daughter 15 is petite but has bloating issues which makes her feel self conscious can anyone tell me in their option would these work?

I also have bloating issues and a bit of an "apple" shape and find these panties very comfortable. They do not hold me in much, but they make my tummy appear smoother under slacks an eliminates "mushroom top." I would either order your true size and test one for shrinkage in the dryer before trusting size. I just hang them up to dry to avoid shrinkage. They are still soft and not stiff and the elastic inside may last longer. My main reason for buying these was that the elastic (latex?) on other panties were irritating and too tight at the waist. These solve that problem as the elastic is inside and covered.

Are these really 95% cotton? The pictures look like a modal blend (from the look of the fabric and the amount of stretch)

I have the variety pack with black, purple, navy, and grey, as well as the beige 4 pack. I'm a stickler for cotton undies because cotton breathes! I would say the grey and the blue feel like they have the most cotton, true to the 95/5. The beige feels the least cottony, still breathes but it doesn't feel like 95/5. Black and purple are somewhere in the middle. But in wearing them they all breathe. By feel I would guess they all have cotton, some colors feel like they have different ratios.

What size for 57" waist?

I have a 49" waist and 55" hips. The size chart says the 4X should fit me, but I found the 4X a little binding, so I got the 5X and they were perfect for me. I suspect a 5X will be pushing it for you, but they are pretty stretchy so maybe it's worth a try. I wish they would make them in larger sizes!