Contests are nice to trigger engagement. I am however not so sure that contests will maintain engagement on the long run, from my own experience. However, I have no idea about what you want to do in details. Maybe I am wrong. Hopefully I am wrong... I am more than happy to support anything that anyone will try. Anything that helps, is welcome. Anything :)
Therefore, if you want steemstem to support the contest, feel free to contact me on discord (before starting the contest) to see how we can help you :)