He or she may or may not charge.. 

I live on Maui where, just like CA, homes sell for 1M, 2M, 3M and more everyday and they still charge 5% or 6% commissions.

Also since it's a duplex, you can't just charge the costs back to the tenants like you could in a SFH.I like how you saved 9% for vacancy, cap ex, and management though!  

I know banks that will do conventional loans with no limit but not portfolio lenders.

the convention is to tack together holding periods upon sale of a property formerly a subject of a 1031. 

What interest rate will they charge?

The bank total charges would be 238k120k at closing 30 fixed at 5.827%The seller financing is a much better deal on the surface, im just worried about losing out on some protections I might get with the bank. 

We spent almost all of our free cash on the down payment, we went with a conventional loan putting 20% down with a community bank in the area (which also happens to be my employer). 

We also charge a little more to rent as well, and tell them we're going to be giving it back to them.

Can you get a conventional loan?