meaning if you know someone who has great credit, have them add you to their High limit/Low revolving/good standing account and you can get the benefits of their credit history, on time payments and credit limit.  

These challenges are temporary and typically revolve around vacancies.

No they are not typically viewed as credit cards but they are revolving debt.

I want to do this so badly, but the conversation revolving around money and who's paying for what is something that's really important for me before I can start the process. 

The issue revolves around the property APN:  If each has a separate Appraisers Parcel number, then each can be bought and sold independently and each then qualifies for a Conventional Loan.If however, both are listed under ONE APN, then there is ONE existing mortgage and BOTH must be sold together AND you need a Commercial 5+ loan.

The latter would set up a revolving credit line that would allow you to quickly access money to purchase other properties.  

My biggest mistakes have all revolved around not screening as well as I should have and being in a hurry/careless about filling vacancies.John Wooden - "hurry but don't rush..."

Install driveway/garage cam. 

Other issues with basement apartments usually revolve around codes like ceiling heights and sufficient egress.

I don't want the rental to become a revolving door of roommates coming and going because that never ends well.