Flat Fee MLS Brokers for sellers have been around for a long time, but Flat Fee Broker/Agents for buyers with a cash credit/rebate of the buyer agent commission are quite new and just starting to get some market share.

Any tips/tricks would be greatly appreciated.  

Connecting with local GC groups in your area will help you connect with subcontractors, find out tips and tricks of the trade in your local area (since all areas and their real estate differ slightly).Also, have you considered the motivation behind building a brand-new duplex versus finding one on the market?

So is this just as simple as showing how much the property makes or do they also look at personal debt to income, credit score, reserves etc as well.

It would benefit a lot if you are able to obtain US credit, US LLC and US Bank Account.

I would say credit monitoring

.- Institutional Capital & Private Equity: By moving from hard money to institutional financing, you can secure larger credit lines with better terms.

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

I have the credit, experience and the knowledge on how to underwrite the deal to show their ROI in this arrangement vs a traditional sale. 

You can decline them off their credit, background and for not having 2 past positive references.