Creative finance question - seller finance w/ hard money

I have an off market multi family, mixed use, and single family rental portfolio with major upside potential in a sought after area. The seller offered me 30% down and 6% interest when I inquired about seller financing. I am in the midst of flipping 7 properties and the majority of my liquid funds went to down payments on my hard money loans for these flips. I am about to sell 3 of my flips, but I probably won't see that money back for at least 2 months. Do you have any ideas on how to put this deal together? At a 15% cap, my offer is approx $742,000. I can definitely get an equity partner involved. Do you think a hard money loan is feasible if the seller is in first position holding the note?