Personified software issues for development team

My task was to create illustrations of personified software issues (tech people call them “bugs”) of three kinds: critical, major, nice-to-have.
The illustrations are meant to be used digitally (viewed on screens) for gamification of development process in bug tracking system. But, as the client said, the pictures would probably be printed on t-shirts and tea cups.
The design was required to be “a kind of flat design but somewhat fancier”. We agreed to make the cards look “more material” with illusion of rough paper and with reverence to the first half of the 20th century.