The builder is already pricing in 10% increase a year as a typical townhouse sells for about 1 mil.  

Obviously you've heard how difficult a time home builders are having due to prices of material skyrocketing. 

Total guess here  they dont want you to accidentally find out how much more you are paying them than they are paying the actual builder 

regular home insurance or builders risk insurance? 

New Home builders are sometimes selling to the highest/best offer, while most work on the drawing/lottery system.

If you can start looking at lots that are zoned correctly and researching builders so when something comes along you're ready.I've been seeing a few more than normal duplexes on wholesalers lists locally in the last couple months if you are looking, not much on MLS though.

Hey I'm coming across a lot of land listings in Dallas and I get things all the time (cold calling all day every day) that I think a lot of builders would like.

Is there a list or a directory of Dallas builders/developers?

Possibly building in the future on the subdivided or selling as builder ready.

If it were me, I'd create a Joint Venture or partnership with a builder/developer. 250k is enough to help you with multiple down payments....or purchasing single property outright.