If you buy 100k property, and sell it for 150k, your gain is 50k (I'm leaving out closing costs on both ends for simplicity).

So I'd only gain about $150 a month so it would take years to re coup my initial investment. 

I agree with Chris, start single family then you will gain more knowledge and also move revenue to venture into MF.  

It would also have about $35,000 equity that I could liquidate to apply towards another property, debt paydown etc.I want to extend my ownership to at least 1 year and 1 day to qualify for long term capital gains vs ordinary income.  

They may be more of an expert in the area.If you have not listened to this show, you will gain huge insight from it: http://www.biggerpockets.com/renewsblog/2015/02/26/bp-podcast-111-unique-profitable-real-estate-niche-youve-never-considered-with-jefferson-lilly/

We will be managing this duplex ourselves to save that expense and gain some experience.  

Yes, the junior lien holder was wiped out but she has the rights of the junior lien holder as far as a payoff is concerned and ability to gain relevant pertinent information on the senior lien.

There is a ton of knowledge to be gained.

If you can break even every month and sell in two years for a $60k gain, then it's worth it.

BUREAU CHIEFShutterstockHome prices in Denver are up 10% year-on-year.Here’s a city-by-city look at house prices, as the S&P/Case-Shiller 20-city composite showed a 0.9% monthly gain for March and a 5% year-on-year gain.Note that the cities are those selected by the Case-Shiller report, and that major metropolitan areas including Houston and Philadelphia are not included.CityMonthly gainYearly gainAtlanta0.8%5.4%Boston0.4%4.6%Charlotte0.9%5.8%Chicago0.9%3.4%Cleveland0.4%1.0%Dallas1.8%9.3%Denver1.4%10.0%Detroit0.8%4.2%Las Vegas1.1%5.7%Los Angeles0.8%5.5%Miami1.0%8.7%Minneapolis0.9%3.0%New York-0.1%2.7%Phoenix0.6%3.1%Portland1.1%6.9%San Diego1.3%4.8%San Francisco3.0%10.3%Seattle2.3%7.5%Tampa1.4%8.1%Washington0.8%1.0% Seasonally adjusted, the March home price gain was an even stronger 1%.