CRESSIIsla Boots with 5mm Premium Neoprene and Anti Slip Rubber Soles Black Size 12

Are the sizes specific to women size? Trying to buy some for my sister "Christmas" she's a size 6/1/2. Is there anyone out there who could help me?

Would the soles protect you from reef beds?

Anyone use these for rocky shore lines? Wanting something like Japanese tabi.

Does the zipper chafe the skin? How about when in fins?