We want to finance it, but the lenders like 21st mortgage will not loan if it’s an LLC. 

If you are getting a loan, they will require you to get "homeowner" insurance, which covers loss of the property due to fire and/or what other perils they may request (flood, earthquake, etc).

I was pre qualified for a DSCR Loan shortly after buying my first house but due to financial constraints to come up with 20-25% of the down payment I feel like I’m stuck.

The loan is paid off in 60 mths.

I just bought my first duplex near Scranton with an FHA loan.

I have an amazing investor lender that does DSCR, hard money, no money down fix and flip, and traditional loans as well. 

It's great that you're looking to turn this situation into a positive venture with Airbnb.I think there is a lot to unpack here to answer your question.

Have you ever considered an interest only loan option?

So, in sum, house hacking can be when you are able leverage low down payments in order to control an asset (use an FHA loan and rent out the other rooms/units, use the VA loan with no down payment to ultimately turn the property into a rental property, etc.). 

Loan Qualification:Rental income from one unit can strengthened myr loan qualification when applying for a mortgage.