My concern with the Fund model is some GP/Syndicators split out the performance of assets individually, meaning that if say there are 5 assets and two are grossly underperforming, but the other three are performing than the GP collects on the waterfall structure anyway for the performing assets (says pref 8%) or a straight split, even though the aggregate performance of all the assets is overall underperforming if you follow me. 

Just in terms of safety, assuming the rents are really that high, I would think you should have a pretty nice margin of safety.

I think their business model is volume not so much margin but again I would not promise they don't take a huge margin on some deals.

ACH is simple, bank-to-bank in a few days.I would recommend you stay away from cash/checks for safety reasons, plus cash is harder to track.  

I’m a bit reluctant since I have two small children; however, I could consider a duplex or something that still allowed our safety and separation from said tenants.

But it's those little cuts that can add up to big hurt if you are stuck in that mode during a pullback when you have to adjust rent and it's now - $200 - $300 a month and you have mustered out so savings are dwindling. 

My primary mode of communication with the seller was through text.

When I’m working with a client and helping them set up a model, I find that using old settlement statements is the best place to start.

After you have a safety net of about $10-15k, then you could be able to sleep better at night as well. 

In short, I'd run my numbers both ways; 1) basic facelift, and, 2) update rehab, to see which makes most sense.Market rents depend on a number of factors; safety, proximity to employment, public transportation (if applicable), features, options, finishes and amenities.