I am in an administrative staff position, in a research compliance role, and frequently have to "cold" email professors I have never met or otherwise previously interacted with. In my institution almost all professors have MD degrees, so I typically address them as "Dr. X." However there are a small number of professors with master's degrees in areas of specialty that don't offer doctorate-level degrees, and I am uncertain how to appropriately address these individuals.
My gut reaction is to address these individuals by their first name (as our institution's culture considers first name acceptable for staff above you in the reporting chain), but to me this feels disrespectful when applied to faculty, especially considering the content of my messages are often directing them to do things (or stop doing things) they'd rather not. Conversely, calling them "professor" seems unusual to me since I am not enrolled at the institution. Finally, my school is very progressive, and I worry about (mis-)using gendered pronouns.
Am I worried about this unnecessarily? How should I address these professors when I can't open by asking how they would like to be addressed?