Is the ongoing property manager absolutely necessary, or can you manage the property remotely once you have a tenant in place?

Seller financing, partner, hard money on the buy, on and on go the options.It's the DEAL that makes the money, not the other way around. 

I ran into the same problem as you, but then found someone with capital who felt nervous about jumping into real estate.

I ran your numbers with a sort of worst case outlook and I'm getting around an 8% cash on cash return if you are planning on holding the property.

To answer the question on going back to the seller, I've gone back on all the previous deals and it killed them.

I ran my number after seeing it, made my offer, justifying my number and she agreed.

Sure, I lowered the taxable appreciation on sale, but that seems to be pointless if I won't pay taxes on the appreciation anyway.Overall, my strategy would be to balance my investments such that my NII from all my investments is close to zero on an ongoing yearly basis (I realize this is optimistic, but I can at least try to get close).

If it's something that directly affects your tenants then it would make your unit easier to rent out and if it's something else like your roof or HVAC then there will be lower ongoing maintenance.

If the city doesn't supply the metal ones anymore I was planning on going to supply house.

I ran those numbers and they are even better.