I used conventional 3% on it with downpayment assistance.

If you are having partners on the deal - see which one can qualify for a second home conventional mortgage and have them qualify, and then write everyone else into the deed and then quit-claim warranty it into the LLC with your partners after you close! 

He is having difficulty qualifying for conventional lending since there isn't rental history (owner occupied) and his business is often cash (unreported income).

Does anyone know the minimum and maximum amounts that an FHA and Conventional loan would approve for the purchase of an owner occupied duplex home in Harris County in Houston, Texas? 

Meaning, on a VA cash out refinance you can take out 100% of the value of the property whereas on a conventional loan you could only take out a loan for 80% of the value of the property.

Conventional 30 year with $6800 down.

Purchase: $405kPersonal contributions: 12k (closing costs) + 15k (repairs) + 20k (5% down payment for conventional loan) = $47kPure Cashflow: $500/monthCash on Cash ROI: 13.33%ARV: $475k?

Put 5% down on a conventional mortgage.

Conventional mortgage with 5% down.

Purchasers with All-cash, conventional financing, traditional FHA loans and (sometimes) VA loans will have a better chance at an accepted offer than a 203K loan.This, however, doesn't make it impossible!