This will allow me to pay down at what would equal a 15-18yr monthly payment if I choose while having flexibility and debt to income of 30yr in eyes of underwriters on future loans.2 Refi only primary and Investment 3 with 30yr fixed loans. 

As investors, we have to be flexible.

Then lay over flexible plywood underlayment, usually called luan.

Private money is also an option, provided the terms are flexible for your situation. 

Something with an unfinished basement will give you flexible space. 

Lender open to flexible debt to income ratio is likely my only hope.

Hello,I recently completed a refinance and now I wish to open a HELOC account as it is a more flexible option to tap into the equity.

The added benefits for me are; 1) I am able to structure/replatt things in a way that gives me future flexibility to be able to sell the units individually or as a whole. 2) I can handpick an "opportunity zone" neighborhood as opposed to choosing between limited selections. 

Bremerton is loosening up its ADU regulations with extra flexibility for existing unpermitted ADUs.https://www.kitsapsun.com/stor...Hat tip to @Mark Canton for telling me this today!

Other half would be long term (well medium term) rentals 1-3 months or so...still flexible and looking for options