To add to some of the comments here, seller's financials are only a small part of the due diligence and are often close to worthless if self-managed.Consider the following:Three furnaces that are past the end of their useful lifecycle will have more of an impact on your returns over the near term than current leases, yet you don't ask for HVAC maintenance logs prior to making an offer.You will be managing this property going forward, not the seller.  

If it's a commercial deal, regardless of what you think, you should look at the cap rate because that is a key indicator to how those properties are evaluated.

So where is the rent vs. live in flip calculator? I am moving for my W2 job, and have the opportunity to rent a 2/2 apartment from my dad in a 4-plex on a street full of rentals, or to buy a nice 1990 built 3/2 family...

You don't have to make any commitments to REI yet, just start with those things and then evaluate if this is the right path for you.

Now it is time to increase your goals after re-evaluating where you want to go. 

The 2% or even 1% Rule/Evaluation doesn't come into play at all.  

@Arnie Guida - I do everything via text / email, and it gets logged in my software to make sure I have all correspondence documented.

I am evaluating a 30 unit complex which is off market.

The 20+ track record is good, but may want to elaborate on that a bit (20 years as owner/manager/rehabber is one thing, agent is another in my mind).2) You definitely have to evaluate each one as it comes.

I think if you are going to evaluate price too, square footage is a good measure for how much you should pay and how much each unit should rent for.