I'd be concerned about being the first few builders to bring a finished product to market since who's going to want to buy and live in a construction zone.

Yes, you will have to put 20-30% down (you can get creative and ask the seller you carry this portion if you don’t have it, ask friends and family, partner with someone, etc.) and your credit and DTI must meet the bank requirements. 

Will taking out more credit cards and paying them all on time help? 

. $205k building, and with a 3.5% fha loan, owner occupied, and in a low to moderate income area, with lender credits, I only put down $4,500 with less than $1,800 in upfront costs, inspection, appraisal.

- damages - to roof from Antenna, Ruined lawn by pet urine and bug patched walls that need to be repainted.2 questions - did anyone had experience of small claims court in Washington, by law do I need to refund everything if I am late beyond 21 days. ( everything was deducted from receipts)Does the judgment against me go on Credit history?

Plus you can get an unsecured line of credit or a credit card with a cash advance or even a secured line of credit on your existing rental property. 

Whoever pull your credit ask them what you can do to get higher credit score.

Not a developer, but I think typically builders don’t want to have more than 25% of the finished product into the lot costs.....seems like your purchase price is too close to the individual lot values, after subdivision.

If you need a recommendation for a local bank on the refi --- I'd suggest Credit Union of New Jersey. 

I would recommend refinancing the first 4 with a portfolio loan to get it off your credit report and then you wouldn't have that issue anymore.