I have really good income & have good credit -middle score is 768. 

I have a US credit score, US bank accounts and some US-based income, but my paychecks are not.

Your credit score needs to stay relatively the same from application to closing. 

With middle 700 credit scores you can push your rate into the mid 6s today.

That's incredible!

If you have a lot of equity or if you bought the property when your credit score wasn't great (leading to a high interest rate), then it might make sense. 

Your property management should send you pretty clear reports at the end of the year so as to obviate your need for such.If you have more than 3 units and self manage I suggest software - especially if you are considering expanding.I find Stessa usefulI also use buildium but not incredibly thrilled with it.  

There are lenders out there that will lend up to 50% of the AV with no minimum credit score requirements. 

Securing loans with a low credit score is possible through private or HM lenders.

A few tips: maintain a solid credit score, organize your financials (especially your proof of funds), and be ready to show that you have a solid plan for your investments.