Your earnings are almost exponential and the investment is bulletproof during market corrections since during market corrections multi-unit properties actually increase in value while single family homes depreciate.Don't burn the candle at both ends and someone like yourself reminds me of the same scenario I see over and over.

In March my tenant burned down my house due to "careless disposal of a cigarette" per the fire report.

Long delays in places like Dallas can cost you a lot of burn rate. 

Wood burns and sheetrock is fire-resistant.

Also check if the wiring is aluminum, I'm not saying don't buy an aluminum wired house but I don't like the idea of my rental properties burning down and if you can avoid it I would unless the deal is sweet enough.

Berwyn and Forest Park both do this a lot and what it means is your unit is legal unless the place burns down more than 50% or goes vacant for a year. 

We're looking into house hacking as a way to start, but we fear it might be too slow of a burn starting at age 29 that might not pay off in the end, especially since we don't want to live in a duplex forever...we have to get out of it somewhere, somehow.At $3600/year, it sounds totally unfeasible to do anything beyond our brokerage $500/month investment as any sort of savings for anything, whether benefitting the house or possible future expenditures and this has been bothering my mind for awhile now and created a lot of stress involved with the house. 

It is so hard to break into this arena and you could get burned until you have some experience. 

I don't want to be rude or burn a bridge, but I also don't want to sign a bunch of these with each wholesaler JUST to get property details. 

I don't want to shoot myself in the foot by burning a bridge with the seller if my expectations are off-base, but I don't want to be made a fool of either.