In New Hampshire, where I am, we run into the same situations with older converted SFH to 2,3,and4 unit buildings.

I've been watching a lot of videos, listening to podcasts, and reading books to educate us on real estate investing.We are in the process of seeking an agent as well as mentorship from seasoned professionals to navigate the complexities of the market today.

When you have gotten a property with a HELOC do you have to let the money "season" in your bank account before you will be able acquire the financing from the lender? 

Do you foresee those older areas having high possibility of excellent appreciation over the next 5-15 years?

(for example no seasoning cash out options that make BRRRR work)

As far as STR’s in FL, seems like everything is somewhat seasonal.

New or aspiring investors and seasoned investors.

So, what you are asking is there lenders that will do 0 months seasoning? 

There is no stability and it is seasonal. 

Its also an ideal forum to talk in depth with other seasoned pro's to avoid lost time and money.