Late rent payments, etc. 

You share the lease, you share his payment history, and you give a total of what is owed.

No, just inform them you are the new owner (they may want proof) and provide them with the address to send payments. 

Unfortunately, I do not have any recommendations but be careful on who you select.

You inflated the price $70k but they are only making $50k in payments.

The more money you save, the lower your monthly payment because the more you can put down.This is really great advice....some of the best. 

That is a valid question, which is why you have to be careful with what you select as you would with any other investment.

This is the first time I’ve had such few inquiries, and my research suggests Zillow might be selectively prioritizing certain properties, like the lowest-priced ones.

They typically have multiple origination points (meaning very high closing costs) very high rates (compared to conventional but also compared to 6 month or longer waiting period DSCR products) and almost always have VERY long pre-payment periods up to 5 years.

I have a family investor that I will borrow from for the down payment, then finance the rest from the bank.