What @Carlos Flores said.Here is some information, but not much.I can't recall for sure, so take the rest with a grain of salt, for FHA multifamily I seem to remember you need to have someone on the team that has done it before, and I believe a $5 million minimum.

I am looking to gather as much information as possible as I am currently looking to start investing in small properties in about a years time.

Currently trying to learn & absorb as much information possible.

Where would you get the information to calculate a cap rate on a 4-plex? 

I would also go to local clubs and get togethers to network and get your information.  

If they don't qualify or do not have the funds, then inform them they all have to leave.....you need to find a new tenant (especially seeing as they are already falling behind).

Many Realtors and/ or Mortgage Brokers will not tell you this information.

Bonnie, I am very familiar with stucco here in south Florida and without more information it is not possible to advise you properly. 

I am looking on information and advice to help me plan to purchase another one ASAP!

PS: I send a copy of the lease to them as well as a house information sheet when I approve their application, before they pay for and submit to the credit and background check.