However, they take credit for their company's transactions.

OPTION 3 – Lease Option Assignment Option Price: $132,000Option Consideration: $50Monthly Rent: $1,050Rent credit: - $200 (on-time payments only)Term: Minimum 2 yearsNote: If we can’t do option 2 and stay in the middle, we will assign the Lease Option to a pre-qualified tenant-buyer, but only with your written authorization.

I have around an 800 credit score and not too much debt.

Since you brought up the point, I'll do some research into other banks and credit unions to see if I can actually get a 4 unit instead of just a 2. 

My credit is good and I have no debt, so I don't anticipate having any issues getting traditional financing. 

It will ping your credit score so don't do it if you aren't ready to look at buying.If you are talking to an agent etc you SOUND like you are a warming up to buy.

What business credit cards to apply for, on my newly formed llc.

Instead of the commission I had it credited back towards repairs. 

You can definitely do a home equity line of credit or cash-out refinance on that property to fund another deal.

Hence, you could have a cash flow generating machine but won't get any credit.