As luck would have it, the property next door was sold days later. 

I have spent more money in wrong and unreturnable items rather than hiring a professional licenced.

But with construction costs skyrocketing and considering how every good contractor is booked for 6 months, you'll end up getting quotes closer to $250-300/sqft.Generally it is not a good practice to estimate the ENTIRE project based on price/sqft, as some items are way more expensive than others, but you asked for a "general" ballpark.

Loan amount has zero impact on your property tax bill and minimal impact on your homeowner's insurance cost, purchase price primarily determines those two items.- If you want lenders to include rental income from the property you are purchasing, then how much that rent is will impact how much you qualify for. - Yes, they really need to see all your paperwork, etc, to preapprove you.

In fact, I would just include a line item in my project budget as a cost to the project.From your perspective, I'm not sure how sustainable charging only $69 to $99 / month is for unlimited design services especially for clients that are doing several flips per month.   

With only 1 transfer since the subdivision and several years passing since the developer sold the lots... low risk. 

The price never change until suddenly the house was sold.

My scenario is that I just sold off 2 of my units and did a 1031 .

If some want to do loans they will bend on certain items.

But basically the houses were listed for a few months and had a few price cuts and eventually been sold below the asking price.