Ok, with headshots, you can likely get away with a crop-sensor camera, but with real estate (RE) and some family shots, you'll sometimes do better with a full frame camera.
All of them are likely going to require multiple lighting units, unless you already have many. (I know a local pro here who does many RE shots each month uses up to six lights per assignment. He rarely uses less than three in a shot. However, going HDR is an option, if your clients like that look. Many don't.)
Any lights you get would also likely be useful for the headshot and family portraits, but you're likely to need different modifiers than you use for RE shooting.
So, with $1000, I'd spend some of it on lighting, in addition to what you already are thinking about. I'd also try to find a local professional, and I mean a real one, not just someone who owns a camera and has a stack of business cards that says they're a photographer. After you've found one, ask if you can assist them; it helps if you can find a local photographers guild and get contacts there.
Don't believe I really answered your question, but that's my $0.02 worth. Good luck with whatever you do.
WM