Ok so I had posted earlier about mission requirements that included the sheriff. After playing around I believe I found a glitch.
So missions that required a sheriff seem to be able to be completed without an actual sheriff being sent. I’ve completed 4-5 missions that required police and at least 1 sheriff. Also I have a community mission running that shows I’ve completed the unit requirement for the mission even though I haven’t sent anything. The only thing it requires is a sheriff.