Many newer investors have to start somewhere and older more-beat-up homes are cheaper and can help someone get their foot in the door.As for appreciation, this too is location dependent.

IE its common in so many areas that the 500k home in Wis sits on a 75k or 100k lot and 300 to 400k is the cost to construct say at 150 to 200 a foot..

Times 200 board foot.  

Because now we eliminated the foot-print of autos.

This being said, I don't believe we'll be able to meet the income requirements to qualify for a conventional.This leads me to believe hard money or private lender is more the only option to get my foot in the door, use my business to make repairs at very good rates, build some equity then refi once the balloon is due. 

I talked to a modular home company in my area, and he said to build a 4 / 2.5 2200 square foot home would be 215k, and then foundation and utilities would be another 160k.

That way, you can get your foot in the door, start building equity, and stay at home a bit longer to save more money.You could also consider the BRRRR method where you buy a fixer-upper, rehab it to add value, rent it out, and then refinance to pull your cash back out.

Id like to understand what the most profitable way to fix up a current 1,700 SFR in a 6,200 sq. foot lot would be?

The footings support an addition.

While metrics like square footage or price per square foot matter, the number of bedrooms, bathrooms, and overall location are often more critical for attracting tenants.Engaging a property manager early on can save you from costly mistakes and help you invest in properties that perform well in the rental market.