That idea is very smart! I've been thinking of ways to fix up a bib for an adult, because I'm simply not impressed by the giant adult sized ones that I've seen on the market. Plus, I love Hello Kitty so I approve of your design choice.(; Very well done, and thanks for the idea!
It is a relatively simple process and takes about 15 minutes to do each one as long as you have the right equipment. Ribbon, matching colored thread, heat adhesive tape, an iron, and some scissors.