He's a good resource for things like this.

When you're fully ready for analysis check out the renter analysis tools and don't be afraid to post questions and ask for help, everyone is really supportive :) A good first step and great lending resource (super important in today's market) might be to check in with my lending guide and bestie of 20+ years @Joseph Chiofalo they lend nationwide and he's very patient with newbies and can help craft a workable plan towards portfolio growth.

BiggerPockets is full of resources designed to help you along your journey, whether you are just getting started or a seasoned investor.

Would anyone know of a good and reputable resource or platform to learn and execute investing / buying  mortgage notes?

BiggerPockets is full of resources designed to help you along your journey, whether you are just getting started or a seasoned investor.

If the vacancy rate is currently 5%, should I allocate 20% for a Great Recession like event.  

This can help you restructure your debt and potentially save your property.Cash Out for Lender Payoff:The refinancing process includes cash out that is allocated to pay off your existing lender.

You can read up on "Disparate Impact" Theory on a variety of landlord resource websites, including government agencies. 

You will learn so much from people who know the market and they will also have resources that will be useful to you.As for the properties themselves, it never hurts to start looking.

There are a lot of great meetings and resources around here that are geared towards investors.