I'm looking for a minimum 620 credit score and no late payments in the last 12 months.

You made the choice to buy a $35k property... that's incredibly cheap in today's market.

Credit karma gave me a score of 711, I know it is an estimate but I found it weird one had a score yet the lender got none.

To my knowledge most FICO scores only go up to 850... but congrats on your score.  

After all, they weren't making them, that's how they go into the situation they're in now.All they care about is 1) how much cash will I give them at closing 2) how much time do they get to move out 3) how much cash will they get when they move out.After I bring their loan current and make 2-3 payments their credit score increases, anywhere from 60-100 points.

I just sold a few homes and was able to score my clients some massive $!

Any tips, personal experiences, or resources you can share would be incredibly helpful.Thank you in advance for your assistance!

My credit score is good at 730, and my monthly income shouldn't be an issue either.

I suspect you return is much higher than you indicated.You have incredible prop 13 discount by now.

 the more competitive rates are  6.9% for 20% down owner occupied, 780 credit score. 7.45 and 1 point for a duplex seems pretty solid.