I always liked the classic style of life presented in the game Bioshock (http://en.wikipedia.org/wiki/BioShock) Which takes inspiration from a 1950’s style. The minimalistic but interesting graphics convey a friendly attitude while giving helpful advice.
This approach to my idea would allow for uncomplicated graphics, that still convey there intended purpose, while having continuity among the posters. The style is very recognizable in comparison to standard vector graphics, and brings a ‘Retro’ feel to the posters.
However, on the other hand, this could give the wrong idea about the posters. Maybe associating the procedures with outdated techniques. If a fine balance could be struck between the retro style and maintaining the focus of the project, then I would be satisfied.