Investors do this because they have to make profits on as many deals as they can.REOs are a side business for banks and they do it because they have to.

I am also considering buying a duplex and living in one side and renting out the other. 

I don't see repairs and cap-ex in your report and that would kill all of your cashflow.The ROI number is prefrence but you have to look at what else you can do like the stock market on average has made 8% which is less work than rentals so if you can't get better than that you could just put it in the stock market.That being said Portland is a hot market, although tapering off, but still hard to find a good deal. 

Now if your in an investment were you think there is going to be some major appreciation or up side that's another kettle of fish all together..

Some will still do a little residential on the side for family and friends or commercial clients that also need to sell a house or two.

The down side for you on using a CC is that you are looking for funds as a down payment too. 

If you give him 50% he is going to disappear quicker than Joey Chestnut can make a hot dog disappear. 

I'm sure it is no surprise or secret that Texas is a very hot and desirable real estate market.

Eventually, I would like to supplement enough income to scale back to a 40-50hr work week at my job and break away from the turnkey side of it to further maximize returns. 

You should separate the passive side from the active side of your business (like, if you are also doing flipping).