Quiltlady: Regarding the amount of fabric: You need a piece 14"L x 22"W for the all sizes. If your knit is at least 58" wide, you can get two from that.
I usually buy 1/2 yd. as it is hard to get just 14". Does result in a little waste, but some shrinkage with washing and drying too.
Good luck and have fun making these. Someone will be blessing you. Penny