They also offer tenants various payment methods, which can simplify the process for everyone involved.

We totally get the premise behind the Brrr method but at the same time, if you can utilize the same cash principle to buy a bigger, better rental house that will appreciate well over time due to location, wouldn't it also make sense to consider using the cash house equity for this bigger location house to be refinanced later at a lower rate and take the equity out of the better location house then and use the equity later?  

What a brilliant idea! 

I'm open to other creative methods such as Cash App, Paypal, etc. ... but I believe that they charge for automatic ACH payments.

Closed off spaces were just as @Bruce Woodruff said, a relic of times when you either had servants that worked in industrial spaces and methods that were a lot more crude than today, or when people were poor and could only afford to decorate out a single room as a "proper" place to entertain guests.

I plan to follow "The Stack" method laid out by Brandon Turner in "The Multifamily Millionaire" vol.

Find Brandon's videos on YouTube for the "four square" method of analyzing homes and practice.

It's difficult to be completely hands off on your first one because BRRRR and flips are active investment methods.

We are following the BRRR method, so I’ve been doing my homework, but have a couple questions for the experienced. 

The BRRRR method is a great way to scale if you have the right team in place in advance.