Possible to Seller Finance Down Pmt?

[Chris A]

BACKGROUND:
I currently own 3 rental properties of which 1 is larger apartment building
Approx $500k net worth
Each property is approx 80 loan to value
Excellent credit score (750)
Very little cash available
Am very comfortable with the rental business and real estate in general

QUESTION:
Do I have the firepower to purchase an additional apartment building? What creative solutions are reasonable?

The property in question would cost approx $750k since it’s been on the market for a while and has a desperate buyer. Cap rate is around 8.5 so it’s a solid but not amazing deal. Is it possible for a person to commercially finance 80% and then do a short-term (10yrs) seller-financed down payment? What other options are there to finance the last $150K (down payment) without destroying the cash-flow?

Thank you!!!!