How was it possible for me to buy a property and not have the loan in my name, keep the previous interest, and not have to apply for a loan and hurt my credit?

As the comment above stated you'll have to find your plans/strategy but I don't think it'll be a bad decision you may be ahead of the curve. 

If you create systems and do your due diligence, you don't have to worry about having bad roommates.

Reach out to a variety of lenders, as banks, credit unions, private lenders, etc., all have varying terms.

I've generally been a proponent of investing in the area and I've done so myself but I tell the good and the bad.

Depending on who you are talking with, they pull from those credits at an hourly rate:Book keepers pull 7 credits per hourTax Preparers pull 10 credits per hourCPA/Attorneys pull 20 credits per hourThey will set up everything up for you without using any of those credits.

If you are renting to college students, I would suggest having a parent sign as guarantor for payment and make sure you run their credit report as well.

@Mel-Drick GreenI think that's not a bad strategy.

Higher income or credit requirements?

I, myself have had bad appraisals on some of my deals.