I sent a low-ball offer, and we went back forth but ended up getting 30K under asking accepted.  

If they choose to stay, make it clear they are accepting the property as is.

This is where the big money is I have heard if you're willing to fork out more money and accept a higher level of risk.

If the seller accepts your offer than you do the full due diligence investigation during the option period.  

Prior to that I went through the education modules and took the test to be able to be certified and make the purchase. 

I am willing to test the waters for awhile. 

Once you have a shortlist, sign up for an account with each one and test them extensively to see how they function.

Not sure if this is acceptable, or was in 1991. 

There are "hot" markets where PMCs can just put a rental on their website and get acceptable activity.

You can count up to 75% of the rental income from each unit BUT you have to pass the FHA self sufficiency test.The FHA (Federal Housing Administration) Self-Sufficiency Test is a guideline used for evaluating the eligibility of borrowers looking to purchase multi-unit properties (specifically, 3- or 4-unit properties) with an FHA loan.