Personally, I'm also seeing a wide range of quotes now from different carriers.

I will say that doesn't always mean a pool table or skeet shooting range or mini golf.

I'm seeing renovated inventory sit, then trade well below list in a large portion of the ATL metro. 

Inventory is up, and there are deals out there. 

You aren't ready based on what you said.NJ is one of the toughest flip market in the country now (Northern) because the prices to buy the dumps is high because inventory is low so the spread is too little for new flippers.

Here is the range of cooperating commissions on DFW duplexes listings active as of last week.

Yes you could sell and get your 500k less taxes and then reinvest but maybe looking forward you need to look at investments with higher returns of 10% range.  

My developer buyer just said he could buy land elsewhere for a better deal if I didn't want to sell.In my evaluations, I could buy land for $20k, for example, but there were lots of lots in the $20-40K range.

Thank you @Brandon Croucier I appreciate you being able to give me a general idea and the range of the rates these days. 

Interest rates are in the 6-7% range... so it doesn't take a rocket scientist to figure out if you are increasing your loan amount by ~$50k, and at a higher interest rate,  your payment has to go up or your terms have to extend.