OsoCozyPrefold Cloth Diapers (1 Dz) - Soft, Absorbent Durable Diaper Service Quality Prefolds. 100% Cotton - 12"x16", Fits 7-15 Lbs. - (Infant 4x8x4)

Q: The listing says 12 but the legal disclaimer says 3 diapers...how many actually come?

No, that legal disclaimer is wrong. We are updating it now. This listing is correct, you are purchasing 12 diapers

Q: what do you fasten the diapers with?

You don't have to fasten them if you trifold them and use them as an all-in-2 type of diaper with a waterproof wrap (just like Best Bottoms, but WAY better). You get the longest use out of them this way, since with this fold the width doesn't matter and they'll fit lengthwise a long time (the infant size will get you from birth to over a year easily--get the 4x8x4 for better absorbency). If you want to fold them the old-fashioned way, you'll need to secure them either with pins or a snappi/pair of boingos...but you'll also need to buy more sizes as the baby outgrows the width.

Q: Are these the "better fit" sizes or standard?

I bought premium 4x8x4 not infant 4x8x4, but the premium is better fit for my 6 mons baby girl. However, its length is pretty long for her, and it covers all my baby girl's tummy. It will fit when she turns to 8 mons I expect. I just can say that they are the same size, but the premium is thicker, so I expect that I can use it longer than the infant one.