Can somebody give me some pointers about:- How do I make it as finished sq ft in county records.

Generally my subs prefer working for me over the investor but we also have a history and reputation ex: they know they're paid as soon as they finish vs waiting on inspections.

Here are a few pics of a recent house we finished and sold in 24 hours for asking price. 

You would have to see if your local city will allow you to GC the build yourself, as described, given its multifamily.I also doubt that one person can finish four units in "several months".  

We just finished and rented it.

This is the residual or remainder of the revenue stream available to pay for land.In many markets, most homebuilders will focus on the finished lot cost.

Here's a rendering of our finished building.

I'm currently finishing up my Real Estate classes and am now over run with brokers contacting me....  

A modern, poured basement can easily be finished and waterproofed IF constructed correctly.  

@Brady Speers, have you seen the Bigger Pockets Diary in the Pro File area, incredible documentation of a start to finish flip, budget, steps, etc.