We have 3 single family rental homes right now, and we recently got the opportunity to buy a storage facility completely seller financed.

Or does it mean any additional fees through closing would be paid by the Seller?

Once its done, its done and the seller has no ability to get the property back except to buy it back from the new owner.

Now, how would I come up with my offer price for the seller?

The seller says the house needs approximately 50K worth of work.

I feel like long term the Hudson County area properties will continue to appreciate as demand gets pushed here from an increasingly expensive New York market.Are there any experienced real estate investor's with their brokerage license that can sit down with me discuss my options moving forward. 

Also, does the seller pay the whole 6% realtor commission?

I am new to getting financing on properties as my other 2 properties I was lucky where the seller let me do payments to them directly on short 5 year loans at very reasonable interest rates.  

The asking price is 115k and I could pay cash for about 90-95k (getting the rest from seller or family).

Considering the seller is motivated , positive cash flow property and the owner is just trying to get it off his portfolio. ....How can you structure that deal