Based on your age & needs, you could consider a variable annuity (stock market) vs a fixed or deferred annuity (more like a long term CD). 

"Crypto based USD" is still fiat garbage. 

Your mortgage is based on the refi when you complete the refi.

Agree , those are all incredibly important as is good property management and the ability to price the property correctly based on your competitors rates( dynamic pricing ) . 

Totally agree , and when a home inspector looks at a house built over 100 years ago and writes a report based on current codes . 

However, I shudder at the popular suggestion to sell some of your investments for tax purposes, often coming from commission-based brokers and financial advisors.

I'm based in NJ and am looking to grow a RE portfolio here.

You can use Airdna & other STR estimator tools to get data on potential income/vacancy based on your location and property size. 

I think many others have touched base on a lot of important points such as price and seasonality.

To streamline the process, I want to ensure applicants qualify before scheduling a viewing.It would be beneficial to implement an AI-based system to consistently and efficiently ask prospective tenants the pre-screening questions I currently ask repeatedly.