That is risky in itself.It would seem a lot wiser to take those individual retirement plans and invest them into something they can each do independently such as smaller properties, trust deeds, crowdfunds focused on real estate based assets, or the like.

I prefer the single military members unless I should be concerned about partying and multiple people living in the house that isn’t on the lease?

The only way this would be possible, at least to my understanding, would be to put the duplex in an individual's name so we could refinance with a bank on a 30 year loan.A question for my fellow CPA's or other's who have done this: how could we make this work as far as taxes are concerned? 

If you have one single lease then they should all, individually be fully responsible for the entire lease.

The key to "safe flipping" if there is such a thing, is to have the quick sale not be your ONLY exit, even if the preferred one.

Do I take commercial policy or will it be home rented to othersAny inputs are appreciated and any preferred insurance providers

It really comes down to preference.

I personally would prefer to do my deals with a private lender at 20% rather than a hard money lender, but you need a track record with real estate before you can attract the attention of one. 

I know a number of individuals whose leases reflect the school year.  

I prefer to have answers before someone asks the question.