Wow.. are you doing this without an agent? First things first, hire a realtor to help you navigate a complicated and possibly tricky transaction where you could possibly regret the outcome later if you don't seek professional advice. The builder isn't going to want you to have one because he wants to take advantage of you. In your case, if you are buying, using a realtor is FREE but it is not legal for agents to pretend to be your agent and give you advise without an agreement as doing such. Of course, anything relating to real estate is negotiable. How is the fair market value going to be determined? You really, really, really need to get an agent to represent your best interests and help you navigate the sale and purchase of each home before you get taken. If you need help locating the best agent in your area, i can help you with that. You are a little out of my area but I wouldn't mind helping you find a qualified agent to navigate a complex transaction like a builder buy out.

Sincerely,
David Brower, Assistant Manager/Realtor
Crye-Leike Realtors
678-982-9600
david@davidwbrower.com