2) Define what a "cash" offer is?

If you can find real estate that offers those two and resources, then that's primo.

Who would you be writing the offer to? 

If your parents have a long-term mortgage on it already when offer to manage the property while they're in the Floridas for a split of profit?

Since the start of the year, I've read a handful of BP books:- Rental Property Investing (Brandon Turner)- How to Invest in Real Estate (Brandon Turner/Josh Dorkin)- Investing in Real Estate with No (and Low) Money Down (Brandon Turner)- BRRRR (David Greene)- Multifamily Millionaire Volume 1 (Brandon Turner/Brian Murray)- Start with Strategy (Dave Meyer), currently readingI was thinking of using the equity to BRRRR small multifamily properties and combine some concepts from both the BRRRR and Multifamily Millionaire books (specifically making cash offers via HELOC to secure distressed properties, ideally vacant to set market rents).

Owners mistakenly ASSUME all PMCs offer the exact SAME SERVICES and PERFORM those services EXACTLY THE SAME WAY, so price is the only differentiator – and they often select the first PMC they call!

Also, one of the universities is adding a medical school to one of the hospitals here, it is due to open next spring if I am not mistaken.

I've decided, starting off, that I'd like to try renting apartments in my current market (Jacksonville, Florida) then furnishing them and offering them to traveling professionals on AirBNB and/or furnished finder. 

That would not even be legal.Anyone telling you different or offering you anything that says it is leads of delinquent borrowers is either lying to you, lying to you and making stuff up or, lying to you and violating state and federal statutes. 

If my unit goes for a higher rent than what Section 8 would allow for this particular tenant, I would offer to let the tenant out of the lease.