That should help you narrow down your goals and give you a good starting point. 

@Matt Inouye, Your purchase price of $464k plus $45k rehab is about 90% of the $570k ARV, which is very narrow and thus risky.  

As the negative answers grow greater, your options narrow, money becomes more expensive, and your chance of funding decrease.

Properties B and C are next door, a 6 plex and a 4plex.  

David,One of your biggest problems with fixing up older homes in my part of TX is that a lot of the homes built in the 80's and early 90's have really narrow (like 24") doorways that enter the bathrooms, because of the configuration of the baths there is no easy way to accommodate the turn radius and entrance requirements for wheel chair access, so you will end up having to do a total gut on one of those properties.

I'm just getting started, and I'm starting to narrow down my focus on buy and hold 4-plexes.  

My wife, Melanie, will be pursuing her Real Estate Agent license once we get there but we will otherwise have no "team members" so any input/recommendations there would be appreciated; our target area will be small multi-family units in, on an A through E scale, "B" and "C" areas. 

I would try and narrow your focus down and start digging deeper.

We've narrowed down a few potential investment locations, including Houston, and we are hoping to see if anyone has any recommendations on specific commercial brokers that have been particularly helpful.

Detroit is an interesting case and if you know the city, you are probably better placed to narrow down the best neighborhoods for potential upside.