You can usually also benefit more by simply using the seller or builder credit to do a simple "Rate buydown".The first rate on the buydown is a "teaser" rate that only last for a short time 1 year for example but a true rate buy down is for the entire term. 

@Henry BaghYou can start with local lenders and local banks and even credit unions some have DSCR options.

Verifying last 2 years of rental history very important!

The interest rates on these loans from the programs are usually at a much higher rate as they do not qualify people based upon a credit score.  

This is somewhat hard to follow but I think what you're saying is that your business partner filed a personal articles insurance claim and they ran a loss history report on your partner when applying for insurance on this duplex?

Hello Joshua, I would look at Amegy bank, they have a 1x close product, and also, look at 1st united bank, very easy to work with, beyond those 2, I would go to a local credit union.

I am a US citizen with a 680 credit score (actually, credit karma shows 680 for one bureau and 710 for another bureau), but I haven't worked in the USA for years, and overall, we are looking to get a DSCR loan.

My credit score is over 720, while my partner's is around 541 (on both Equifax and TransUnion), due to a collection that we've since paid.

As long as you mom can qualify on her own (with her credit score), I don't think adding you to the loan application would hurt even though your score is not good (but I would still double check that).

I have a nearly perfect credit score and I'm gambling on that for my first project.