VA Loan, house hack duplex 25% down?

[Sonny Dong]

I want to use the rest of my VA Loan I have already used $315,000. I live in Texas and have one primary residence and eligible to get another property in June (1 year mark). There is a duplex new build and their agent told me this. (They are unaware of me using a VA Loan). :

Duplex is listed for 515,000

“The 4.25% is a 10/6 arm, conventional loan, Fannie/Freddie product, amortized over 30 years. There is no prepayment penalty. It is fixed for the first 10 years and then after the 10 year period, it can adjust once every six months thereafter. Once you close with CMG you are automatically enrolled in their rate rebound program. If you refinance within five years from your closing date, they will waive all lender fees on the refi. They also give you a $1000 credit towards a third-party fee such as an appraisal fee. You pay absolutely NO points; the seller pays them all. The down payment required is 25% per Fannie/Freddie rules for a 2-4 unit property.”

This is from their seller agent. I plan on living on one side of the the duplex. I want to rent out the otherside and my first home would be completely rented out to cashflow positive. 

Can I use the rest of my VA loan or can I use an FHA 3.5% down? I personally don't want to use FHA.

Also I am 100% Disabled veteran are both of my properties exempt from property taxes or just one?

Sorry for the noobie questions I tried using google for most and I just want unbiased answers instead of people trying to make me a customer.