Some will be ok in 2nd position and some will not and force you to refinance out the first - but those are options that are probably cheaper than credit cards 

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

@Helena Goyvaerts rate for a 30-year fix would be at least 8.5% with some points (1% of loan amount).Most DSR lenders have a minimum credit score requirement from the applicant.

I usually try to get 10k but sometimes its not possible and I would prefer to make something and give the investor a good deal rather than make nothing trying to move a bad deal.

After 5 months we had a bad water leak under the house.

If you start a JV in name but do not give your partners proper control and decision-making rights and the deal goes bad you open yourself up to serious consequences which can lead to SEC violations with extremely high fines.Lastly, you can offer the project up to investors who have no voting or control.  

@Kyle TrotmanI would suggest speaking to local banks, and credit unions.

This includes credit, criminal, and rental history checks for all parties.

But it's a risk.If the PM is that bad, I suggest you do some research and find another manager.Remember: cheaper doesn't mean you'll make more money.Start by going to www.narpm.org to search their directory of managers.

A line of credit won’t commit you to a monthly payment unless you use the money, so you can avoid paying interest when it’s not in use.