Then look at your options. 

.$1,500/sq. ft.Step 2: Adjusting for SizeSince the planned home at 245 Seaside Dr will be 4,000 sq. ft., I used an estimated price per square foot within the market range:Conservative: $1,200/sq. ft. → $4.8M ARVModerate: $1,350/sq. ft. → $5.4M ARVHigh-End: $1,500/sq. ft. → $6.0M ARVPremium Luxury (based on 4 Dewey Ln & 597 Beavertail Rd): $7.1MSince 245 Seaside Dr is a prime location and waterfront lots in Jamestown have high demand, I conservatively estimate $1,500/sq. ft., leading to an ARV of:4,000 sq. ft. × $1,500/sq. ft. = $6.0M – $7.1MStep 3: Justification of ARV at $7.1MWaterfront Location: High demand for oceanfront properties in Jamestown.Luxury Market Trends: High-end buyers are paying $1,200 – $1,500 per sq. ft. for new construction.Comparable Sales Support: 4 Dewey Ln and 597 Beavertail Rd confirm the $1,500/sq. ft. estimate is realistic.Low Inventory: Waterfront lots in Jamestown are scarce, increasing property value.Your ARV analysis looks pretty solid based on the comps you’ve used.

At least by my take.

Looked at HELOC on the rental, but is not allowed in Texas.Will probably apply for a 0% APR CC for a lot of expenses/material , but still need cash for labor/ vendors.Looked into personal loan , but 2 banks stated loan can not be used for investment property.

As the largest investor in each loan, we do receive the points at closings. 

If the property doesn't close and somehow the seller doesn't sign at closing, what happens then?

ended ended up at retirement with 0 - $500,000 in net worth from real estate investing.  

Just look at facts.

The thing that you have to remember is that the path of progress and a neighborhood "turning over" moves at a glacial pace.

Raise all $1.6 million at the outset, but call for the capital in stages.