I was recently able to pick up these two, from the 2006 and 2007 Sports Illustrated for Kids sets. I'm not sure why these two were so difficult to find. One Ebay seller listed a whole bunch of SI for Kids cards and I snagged both of these.
With these two I've now completed the run of Cubs in SI for Kids. The sets run from 1989 to now. Despite the long span, the set is made up of athletes from all the different sports, not just baseball, and the Cubs total is just 14 cards.