The attempt was fairly successful, but I am glad that I did do a practice, since there are a few things I will change when I make the Christmas pjs. Sewing knit fabric is not too scary, but mine did stretch a bit in the bottom hem, making it look kind of wobbly. I plan to remedy that by adding a kind of binding to the bottom, wth gap at the sides so that it still has some give.
We'll have to wait and see how it turns out, but for now, I'm happy to have overcome the fear of knits!