So as an investor, am I able to negotiate down the 2nd with that lender, before I purchase the property directly from the owner?

As a business owner I had the joy of this process. 

The current owners have been in it for 16 years and took great care of it.

Remember, if they have leases then you can't force them out just because you purchased; leases run with the land so you are bound just like the previous owner.

Its a single owner property.

In chatting with a few mortgage brokers, I appear to be limited to 65% LTV, as a "cash out refinance" for a non-owner occupied property.   

I'm sure these properties will cashflow, but will provide some serious headache to the owner, even if the property is not self managed.

So I think owner financing is an appealing option to them.I also have an interest in flipping.  

The financing you can get with owner occupancy is awesome... and if you're moving out of a house you own, then you have another rental there.With minimal experience and/or minimal funds, it's hard to get the highest returns possible.  

These have all been owner-occupied properties that mostly belong to our group.