I’m looking to purchase a home, ultimately an investment property, prior to finding employment, making traditional financing unobtainable.I have about 90k is cash reserves and approached a family member with the idea of loaning out some cash (around 100k) to earn interest, for me to buy a property outright.

Most likely when your GC gives you a quote they are pricing out "contractor grade" (standard nothing fancy) selections and will not always fit your criteria of what you want to ultimately choose in the end.  

I'll use an example with similar numbers because I want to truly understand the reasoning here:On the high end, the interest rate would sit around 5.75%, at the cost of -.125 points (ultimately resulting in a lender credit of $164) and a P&I of $766 per month ... on the low end, the interest rate would be 5.375% at the cost of 1 point (around $1300) with P&I of $735 per month.Given that info, this is to say that if I planned on holding onto this property more than 42 months (that's $766-$735= $31 per month... then $1300/$31=41.94 months), then it would make financial sense to pay down the percentage rate up front at 1 point because beyond 42 months, I'd be saving money every month...

You can confirm that they met all requirements, if that is their concern, but ultimately another applicant was chosen. 

While this put a strain on the operations, we were able to execute unit interior renovations much faster than anticipated, which is always our ultimate goal.

If you find that you actually want to continue with STR, like I did, you'll ultimately want to buy as @Ryan said. 

If you know your target market and you are looking to hire a property management company, I’d suggest vetting them throughly early on as they will ultimately lead to the successful performance of the asset.

The ultimate guarantor on any loan secured by real estate is the property.

I'd say I have a 50/50 chance of sub-metering (which would be the ultimate win), but if not I'm feeling confident I can still make a huge dent in the bill with low-flow toilets and a comprehensive plumbing inspection. 

Ultimately I have determined that my LTR portfolio will continue to be my bread and butter but we may try to get a STR as a supplement.