I bought a townhome with a VA loan in August 2014 and our renters took over in June 2016.

I assume that you have owned your current duplex for some time, that it was a rental and it is currently under contract to be sold (as opposed to under contract to be purchased)No --- Duplex I am selling was purchased in September - I bought this duplex to complete a 1031 exchange on a duplex I had sold April 2017 and owned since 2006 with a sizeable (to me anyways) capital gain and depreciation recapture2.

She already brought $15,250 out of pocket when she bought the home so her total outlay on this property is going to be $100,000 or so.HOWEVER, there is another loan type - "portfolio" loans. 

Here are the numbers I've calculated  based on 80% refi of all 3 properties, at 30 years, at 5.25%:Item                              Current                 Post-RefiCash available         $        0                   $300,000 +/- Cash Flow/Year       $   65,000              $  52,000 +/- Re-invest $300k from Cash out as 20% DP on more properties (there's an even better way than this too)& using the same ratios of ARV to NCF, you could increase your NCF an added:  $78,000/year; to $ 130,000/yearYou are sitting on a Gold Mine here, and you're thinking like a "homeowner"...not an investor...although you're not alone.Your Options:  Limited by the maximum Cash Flow from existing properties after complete payoff Max CF/Year                                                                                    =  $   95kCost to do this (pay off all mortgages using your cash)          =  $  456kNet result                                                                                        = - $ 361K  (that's a loss)REFI ALL Option:  Limited by ???????                                                                                                             

I bought my first home using a VA loan as well and the process was super easy and straightforward.

I have around 100k in equity in my house now which was the first house I bought.

Here are some I would recommend (presuming you're looking to do buy and hold rentals):Personal Development: The Science of Getting Rich, Miracle Morning, The 7 Habits of Highly Effective People, Be Obsessed or Be AverageBusiness: The E-Myth, The Millionaire Fastlane, Good to Great, TractionReal Estate: The Millionaire Real Estate Investor, The Advanced Guide to Real Estate Investing,Finding and Funding Great Deals, The Book on Negotiating Real EstateI've also heard good things about How I Turned $1,000 into Five Million in Real Estate in My Spare Time and bought it but have yet to read it (as I'm not in rentals).

We bought it in 2015 and it has gone up in value quite a bit.

I would talk to your CPA first.I have bought at year end to decrease my liability and or increase my passive loss from year to year..

I listened to Scott Trench's "Set For Life" for free using a trial membership of audiable.I bought Brandon Turner's books on real estate investing.