We will be purchasing another long term rental (single family) before the end of the year and plan to BRRRR properties until level 1 of passive income is reached (7-8 years/10+ properties).

Someone could be worth 50 million but if they have no guarantee or a single entity remote LLC it is worthless.You could have all that other stuff and they could simply walk away and keep running other locations of their businesses.If they are a large corporation you want to see if they are credit rated and then if investment grade BBB- or not.

(not so important but if they only require 15% down on a single family home that is usually a good sign that you are working with a flexible lender) Can I change title to my LLC?

Single Family Home. 

The plan is to sell my single family and buy a 3 or 4 flat.

I have a sale leaseback deal with a single tenant that will sign a ten year lease.

I own a rental property (a single family house) on a street where they're building a large "HUD 221(d)(4)" multifamily housing development across the street from the house. 

In addition, I'd like to either house hack my first single family house  or owner occupy a multi family (under 4 units) as I progress in my self mastery, personal finance and real estate education.

It’s just part of the single family market. 

My first rental property is a single family 2br/1bath, rents for 1300/month no issues.