Now I am exploring to buy residential property through LLC.

most lenders  will  utilize the  schd E rental income average  method  for  including rental  income for  qualifying ...if the  proeprty is  recenlty  purchase the  vacancy factor  approach is used 

I like this approach as its the slow and steady method to meet my goals. 

And be aware that there are many who do it in spite of their methods being technically illegal.

We have our primary residence that has a good amount of equity and would like to use that leverage to find ourselves our first flip or longterm rental using the BRRRR method.

This forum is mostly for 1-4 unit BRRRR method properties.  

The correct, professional method of collecting information is to communicate with the Seller's Agent, not the Seller.You also have no right to contact the tenants prior to closing.

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

Paying all cash for everything got me to this point, (it also got me into this situation) and my concern is that straying from my methods will hurt the long term real estate intentions.

I would not utilize room count as your allocation method- it's too vague.