This is just a clean and simple longies and shorties pattern that I wrote up. It has a lot of written instruction as well as links to my favorite URLs for things such as short rows, KFB increases, and i-cords.

I took and included a photo spread of the crotch gusset to leg split process as well.

This pattern can easily be modified for other styles of baby pants and you can change out the included basic waistband and cuff styles (3/2 kitchener and seed stitch for cuffs) to things like kitchener, ruffles, flares, curled legs, etc.

For non-diapered children or disposable diapered babies, use only the middle 8 stitches for the crotch bind-off. 14-16 are used for fitting over a fluffy cloth butt. :)