But if you want to build a business around it you must first become a student of the game, surround yourself with experts, and build healthy relationships with people you trust. 

Cash is great but if you have healthy income you don't have to let the lack of a big bundle of bills stop you from getting started - you just need to know that if you ran into a problem, you could access the funds to take care of that problem, and you could pay those funds back in a controlled way without skipping your mortgage payments or having to go to a soup line for awhile. 

I will go to the building department. regarding the property I am looking at what would my bank do prior to closing a loan secured by the property to make sure there was no contamination in the soil?

That gave you a healthy equity position in your properties. 

I've disturbed the soil frequently.

The house was built in 1980 and the soil in the area is bentonite. 

Understand what that MAO is and make the offer that gets you to a point of healthy returns & cashflow. 

I exchanged messages with another (very generous and informative) investor recently about seller financing and he described it like you, with the healthy down payment and slightly higher interest rate, but I couldn't wrap my head around a buyer with $25k in their bank account who can afford a higher interest rate and slightly higher monthly payments that couldn't qualify for a traditional loan.

It all takes time, it takes time to build trust, to create healthy relationships with those in your industry & market & it definitely takes time to build a successful business.BP is a great resource for information on any type of investment relating to real estate, you just have to look for it for like 5 minutes.

With the dry ground and soil conditions, foundations tend to move quite a bit.