To avoid getting 4 separate loans, I'd like the seller to combine the 4 lots into 1.

It's the combination of no funds, bad credit, almost too good to be true deal that make me say this. 

Wholesaling combined all the difficult parts of real estate, lead generation, marketing, sales, contract knowledge, construction knowledge, ARV knowledge, etc etc... personally I see wholesaling as an advanced technique yet most start there.You can try and get contractors to give you bids, but that will get old quick after giving you 10-15-20 bids and seeing $0 return.

The technique you describe is a combination of owner financing and lease option.  

I like to use 15% combined.

Unfortunately, that makes both you and the deal a very high risk combination. 

A combination of drying up funding, high stock evaluations, historically low interest rates, debt per households, etc. lead me to believe a sharp decline is upon us in this decade.

Most people will not have the combination of ability, resources, determination, and skill to self-educate properly before starting in, and that leads to lots of messed up deals that mess up the lives of real people and the most valuable financial asset they have. 

@Alex Liccione Look for markets that have the best combination of cash flow and strong economic/demographic fundamentals.

For purposes of this definition, an individual or entity will be found to have engaged in a pattern of business if the individual or entity by itself or with any combination of other individuals or entities, whether as partners or common owners in another entity, has engaged in one or more of these practices on 2 or more occasions in any 12-month period” In short- You'll need a real estate license to assign contracts if you do more than 2 deals in a 12 month period.