We are very interested in the buy and hold rental model.  

The house was completely re-modeled upon purchase and in a way that made renting out the bottom seamless: 1,600 SQFT up and 1,600 SQFT bottom, BOTH having 3bd/2ba, each having FULL range kitchens, laundry rooms, living/family rooms, dining rooms, completely separate entrances (walk-out basement accessed around side yard), and bifurcated parking spots.  

I guess that depends on your business model and goals.

Zillow is, as others have stated, a business model based on getting you to their free site in order to derive profits later via other means. 

We are being very conservative in our underwriting as I would prefer to remain static with little to no vacancy (<2% forecast for the coming year based on present leases) than add 50 units which we might b struggling to carry when the market moves to a further increase in vacancy.

I have recently become very interested in the wholesale/ flip business model as I am a licensed realtor in Texas.I came across my first wholesale deal this week but I want some assistance as to what would be the best way to handle this transaction.

@Andrew Auger nice model.

Also, I would factor all of the future maintenance with a PM or contractor in the cost model. 

With interest rates forecast to raise slowly in the next 10 years & the government GPD forecast to not hit 3% for 10 years I don't think wages are going to be climbing very fast.

This is a fact that we all have to deal with, however I wouldn't put too much emphasis on it in regards to your business model.