Very tough to do without good track record or being world’s best salesperson,in general there are not short cuts.  

Without more context, it's impossible to know whether the owner financing terms are reasonable or "ridiculous." 

He gives a discount on his hourly rate for rental property owners in hopes of making a long term relationship.

My goal (and that of most of us in real estate, I imagine), is to build long term wealth and generate enough income so that I don't have to work a typical 9-5 job.

Beyond that, with 38 fet of height you can avg. out to about 8.5 feet ceiling heights if you are to build 4 stories but that usually short changes the commercial space, so you may conclude 3 stories is more prudent (depending on the marketability of the commercial space and number of residential units you can build).2.

The game is to keep loosening credit to bolster the economy beyond sustainable limits, then quickly contract it.

Lenders may require additional documentation or have different terms for new construction.

I am thinking long term in planning what is best for my specific situation. 

You don't have an apartment with long term renters where you have time. 

Hello Ilya,Where are you looking at purchasing your 1st property.When converting a property from a single family to a multi family, you will need to check on the zoning requirements, depending on your location, not every location has zoning.As far as lending goes, it is far easier to finance a single family up to a quadplex, than financing 5 plus units, the DSCR Market for 5+ units is extremely low right now, and there are few if any lenders in that space.For financing 1-4 units, there are Millions of dollars chasing those loans, so you can easily obtain long term financing, at rates between 5-7%.Please reach out if you have a property identified, and I can help you with financing options.