I think they are the perfect age for an I Spy quilt. If you go into your LQS and get 1/4 yard of several cute fabrics, you could do 2 similar quilt tops. Maybe you have some fat quarters in your stash that will work? You could get the story book fabric and do them each a quilt that they could read every night. The pillowcases are a super idea too and easy to make and take. Another cute idea would be a Bug Jar quilt for Alex and a Candy Jar quilt for Charlotte.