I saw your post for the first time tonight. Have you thought about muslin for dolls (skin type)? And if that type of material would work there are probably solid color fabrics that would be great for skin tones. If there is a Joann's or Hobby Lobby near you they often have 40% off coupons in the sunday paper. And you can also sign up online or in the store at JoAnn's to sign up for coupons in the mail. I didn't have time to read all the posts so I hope this isn't repeating someone else's suggestions.
How large are the boy doll's heads in circumference? I knit hats for premie babies and found a few free patterns online for them. Lion's brand site has quite a few free patterns too. If you let me know the circumference I can try to locate a simple pattern for you and send it. I think your dolls are wonderful and I'm sure the children love them very much.