Goal is long term rental buy and hold.

If you're buying a true investment property (meaning you wont live in it), FHA is completely off the table and Conventional/DCSR will require 15%+ down.

Since this will be a cash buy, do I need a seasoning period for a DSCR refi?

The best course of action is talking to so many sellers through your marketing that you find the ones that are truly motivated at the price you are willing to buy their property at..

I'm in the knowledge gathering phase - more time I spend here in BP and other online sources, more I am realising there is a lot more to this than simply buying something off of redfin and renting out

Great interior pictures and someone does a drive by and exterior is in poor shape, no one in buying it. 

However, if you intend to work with a hard money lender or utilize a short-term loan product, you're on the clock for repayment, which can be stressful if things go sideways. 

As a CFA you probably know the old quote from Warren Buffett who said something like "buy what you know and understand". 

Investment Info:Large multi-family (5+ units) buy & hold investment.

In 2008 a friend of mine spend $300,000 to buy 100 houses in Detroit.