My girls like some stretchy sort of knit jeggings at GAP kids although I have to say I am appalled and how quickly they wore out. We also had some stretchy cord jeggings with soft waist and pockets, I am sorry that I cannot remember the brand! Most of our stuff is second hand.
My girls are super into soft comfy clothes and one refused to wear jeans up until the last 6 months. However, I am not ok with straight up leggings and a tshirt. It's also against dress code at our school.
maybe these?
http://mobile.kohls.com/product/prd-...-girls-4-7.jsp