Financing a Duplex that's leased through May 2025

[Butch Greene]

We've been eyeballing a place to put our junior in college but we don't have the income and down payment to buy a 2nd home outright or the 20% to do it as commercial.  A property just popped up FINALLY close to campus, would be perfect for our junior (and OUR FRESHMAN who can live off campus May 2025).
BOTH sides of the duplex are leased until May 2025.  We could do it as a primary residence for her if the 1 bedroom side were open. 
Is there an alternative finance method to buy the property? We'd have a duplex an easy walk from campus. A daughter (if not BOTH) to put in it come May 2025.
20% of $550k for a family with 2 college kids is a ton.
But looming college loan debt from their housing is worse!