Most commercial lenders want a 680 credit score,  or they won't talk to a borrower.      

I would pay them separately rather than giving a rent credit.

That's a terrible reason to do anything. 

The trashing of his credit threatened his job.

Sadly, there are quite a few people over 65 on the verge of losing all their retirement money they put into these guy's investments that are doing terribly while they both go start new ones.

So I want purchase it as my first rental property it's going to need rennovations for sure not terrible shape just older rancher home.

It may or may not show on a credit report, depends on the servicing and you should have the loan serviced.Failure to include the debt on a future loan application is mortgage fraud, wanna go to jail?

Their pro formas felt optimistic with providing 6% annual appreciation and property management that is only about 6% of rent so I take it with a grain of salt (they offer their own property management services but it has terrible reviews on Yelp so I would probably go with someone else). 

Quote from @Joshua Christensen: No offense, but that's a terrible idea!

Terrible IMHO.