I don't think they're "members" of the local government, although they are employees of a local government body. In Maryland, teachers are employees of the local school system, in your case MCPS. MCPS is administratively and legally separate from the county itself (though obviously intertwined) and is run by the elected school board. I guess the question would be, do you consider a person who works in the county assessor's office to be a "member" of local government? Or maybe more analogously, how about a park ranger for M-NCPPC (another local body that is not exactly your county government)?