As @Bill Brandt indicated, virtually every economist’s study indicate rent control is bad for the majority of tenants and the neighborhood, but politicians continue to pass it in new areas.

How many lines of credit would I need?

My credit score is between 750 and 760. 

Johnathan - I've used unsecured lines of credit to purchase and rehab properties in a BRRRR strategy before.

I would definitely plan on using credit cards for any purchases when I would go to keep a paper trail.

The floor is really bad in my empty unit.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The one thing I regret most about real estate is that I did start young, I bought 2 properties with 14 doors by age 22 and lost them due to a bad partnership.

If they ask why, I've always said so both our credit isn't burdened unnecessarily. 

My story is not even that bad.