From what I can tell, that property is where Donna and Harvey moved after they sold their place in Coral Springs. They are probably renting it. You can see Donna leaving that building on the undercover police video they showed on 20/20. It makes sense that Wendi used that address to register her PA as she was probably living there at the time. When she moved out, she changed the address. Charlie most likely lives in Broward closer to the dental practice.
I find it odd that the local press is not constantly confronting all the As outside their homes and business and sticking cameras and microphones in their faces. They're unlikely to say anything meaningful, but that doesn't mean the press shouldn't try, and even video of them hiding their faces and scurrying away makes for great TV. And how about interviewing the patients going in and out of the dental office? "Excuse me, ma'am, do you have any comment on the fact that your dentist has been named by prosecutors as a suspect in a conspiracy to murder a law professor up in Tallahassee as a means to resolve a nasty custody dispute?" That's classic local TV news fodder.