I work closely with on of the branch managers in Queens, New York.They've done 5% down conventional loans for house-hack clients of mine and can also finance condo deals. 

I'm confused by your question...is the funding you have that's not hard money conventional financing?

I made it all the way to the appraisal....paid $500 for it, and was told that I couldn't get a conventional loan until April 2020.

I'm curious of anyone has any perspective on getting a hard money loan for the build and cash out refinancing the DADU with a conventional mortgage? 

Commercial loans are different from conventional in several ways:1) They are typically not fixed rate for the entire term of the loan. 

For conventional loans he is 100% correct. 

Then, when it’s time to purchase the third property, you could refi out of the first FHA loan (if you have enough equity), and then use your FHA loan again, or use a conventional loan product.

I thought about getting a personal loan so I can have the cash in hand when I find the property bc all the good ones go pretty fast but this will limit my buying power and I'll be paying higher interest or sell my condo so I can qualify for a higher conventional loan and only have to come p with the 3-5% as supposed to 20%.  

conventional financing How did you add value to the deal?

This is hideously expensive.Closing Costs to Sell - ($300k * 3%) + flat fee listing $4500 = $13.5kNet Profit  - $ 20k House 2 : Single Family Home 4BR / 2.5 bath, 2900 Sq Ft Listed Price: $275k (would like to offer $260k)ARV : $420k (~$145sq ft based on comps)Closing Costs - $6k minus 1.5% kickback from buying realtor = total $2.1kFinancing- Assume I could use a conventional loan - 5% interest / 6 months= $6.2k (open to suggestions on financing)HOA - $300Taxes - $600 * 6 months = $3.6kRemodel Costs - $90k - The home has very dated finishings, definitely an elderly persons home.