Her and her littermate aren't and will not be born for a time. (the time in which the story takes place) They come when Leaf'dapple finally pushes through her fears and tries once more to be what she wanted to be in the first place, a mother.
Wild'kit, depsite the name, spends most of her time snoozing or playing with the tails of unaware warriors, getting in trouble more than once for trying to follow frogs out of camp.
They both are unaware of what happened to their previous biological siblings, as Leaf has yet to believe they are ready to know that. The two kits do spend time with their adoptive siblings, Moss and Sun, although they are more keen on visiting Sun in the med den.