This town is very small in population (population trend not growing) although has a community college that is less than half mile walking distance from ANY of the properties (community college population is growing at WELL above avg rate(dorm rate 850mth))

I have a million classified posts showing the style we build. you'll never get the numbers at that rate. your numbers are way off and way too low. work with an experienced general contractor who knows this stuff. 

In many cases the wire coming into the house is not rated for 200A.  

BTW this will also help you understand local rent rates.

Heloc I think we could get $175k, maybe DSCR, I am a veteran with service connection disability rating 40% but with my mortgage and car loan not sure I could make debt to income work.  

I dont mean to be blunt here but these all feel like questions that your agent should be giving you guidance on since they know the details of the purchase, the comps, the interest rates, the projections for your investment etc. 

Those two together create equity.Here's what I want you to understand about “buy and hold” residential real estate:Let’s use a single family home with a property value of $300,000Let’s use an initial loan amount of $240,000Let’s use an interest rate of 7.25%And I’m going to give you $150 of cash flow per monthUse a 5% appreciation amount for your property per yearLet’s see what happens after 5 years:After 5 years…$150 of cash flow per month = $9,000Your mortgage has been paid down to $227,000 = $13,000Your property is now worth $382,000 = $82,000So that’s $9,000 of cash flow, $13,000 of principle buy down, and $82,000 of appreciation.

Even under this scenario, with a 50/50 split, you will not be getting paid for doing all the work.Another option would be for you to put in 50% of the purchase price using an LLC that you own 100%, borrow the remaining 50% from your investor as a 2nd position loan at a fair interest rate with points, and borrow the rehab under your personal guarantee.Better, if you can find a lender who will lend to a newbie, and they are out there, you could borrow the purchase money using some of your cash as a down payment, as well as all the rehab funds using a construction loan.

(Floating rate loans, with no rate cap) 

Wanting to explore other options or find out other financial strategies for trying to build a detached home on our lot without having to refinance out of our 2.75 interest rate with a cash out or doing a HELOC.