Yes! Adding the full-color portrait bonus and cameo in the story part of the BE IN THE COMIC tier will be $40/person. So for a total of three people (let's say you and your two kids), you'd choose the BE IN THE COMIC BUNDLE and adjust the amount to $180 ($100 plus $80 for the two additional people) to your pledge and when I send out the backer poll, make a note that that's what the extra money is for.
Similarly for the CHIBI BUNDLE, you can select that tier and add $20 per person for more chibi commissions.
(Note that in both of these cases, you will NOT be receiving more than one copy of the book or any of the other physical rewards.)