My only concern is that the introductory/basic plan has a 5 envelope limit - assuming this is a monthly limitation - and I may have 5+ applicants that are duds before landing on one that I am comfortable with based on screening criteria etc...

Basically it will tell you the demand, pretty cool tool.

Basically if the Townhome cash flows well its almost an easy slam dunk deal.

But my real estate investment knowledge is very limited to the basics that one always starts buying it as their primary residence. 

Start by mastering the basics: find motivated sellers, build strong connections with cash buyers, and never stop learning.

Here are some ideas to get you started:1.Educate Yourself: Start with the basics—read books, listen to podcasts, and watch real estate videos (BiggerPockets is an excellent resource).

Independent contractors only get basic training.

Ceiling fans need to be secured differently than a basic ceiling to be stable and this is of course electrical work so allowing a tenant to potentially do it is a liability issue if they got injured. 2.

In the meantime, take care of the financial basics.

Basically, your question does not have a generic answer.Here's some reading to start:https://www.biggerpockets.com/forums/51-tax-legal-issues-con...https://www.biggerpockets.com/forums/51-tax-legal-issues-con...