I believe only in easy, seamless knitting projects for my patterns. All three items of this ensemble are knit in the round on circular or double-pointed needles. There are no irritating seams to bother delicate skin. There is nothing to sew other than weaving in loose ends, and there is no way around that really (unless you're a knitter who works them in as you go. Knitter's choice!)
The entire ensemble requires Caron Simply Soft Acrylic Yarn or other soft yarn. You be the judge; I prefer children's knits to be machine washable and slightly machine dryable and then hung or laid flat for a few hours until entirely dry. It requires 2 skeins of Color A, and 1 skein each for Color B, C, and D. The needles required are size 6 (circular and double pointed, preferably starting with a 16 inch circular needle and then progressing to a 24 inch later if desired. The leg warmers I knit entirely on double pointed needles.
Now, this outfit can fit a 1, 2 or 3 year old with little modifications