It's a great way to drive revenue on a SFH, assuming you have the space for it.

1) Not investing - Not investing in this asset class is the ultimate, biggest mistake you will make with your finances.

The cash flow on the 5 would certainly out perform the 4. 5 units also spreads your monthly revenue out over more tenants giving you more cushion from vacancies.I'm curious about the reason someone told you to go with 4 units. 

Of all the people I've helped over the years the biggest question I've had for THEM is "Why didn't you get started?"

I have heard from several seminars, meet ups, mentors, etc. that one of the biggest mistakes new investors make is that they pay contractors money up front and end up getting ripped off (the contractor never does anything and just takes their money and runs).

., etc.) but not until you hit $1.1M in revenues. 

You have lost two complete months because you were only willing to sacrifice $1.8k in revenue. 

The biggest difference is that you now have 75% of someones net worth and as a society we have decided it is a licensed activity....

You mentioned the area, and that seems to be my biggest concern for now- its crime rate is 52% higher than the national average, but it has 13% fewer police per-capita than the state average. 

I heard that Texas A&M has one of the biggest Campuses in the state.