A: 6 cap is the kind of cap rate properties get in Manhattan. If this is an A grade property in a prime commercial district you can tell your investor that its a great property with upside in appreciation. Though that statement would probably be a lie unless you were in Manhattan.
What you need to do is find out what your comps are. If comps in your area are showing that properties are selling currently at 6 cap then maybe this would be reasonable but most places in the country are not selling at those prices. By finding what cap rates are for nearby properties you can find the true value of the property. If you find that properties nearby are generating 6600.00 NOI as well, but selling for cheaper, that is just justification for a lower offer. However like I said if you find that cap rates in the neighborhood are 6, then so be it.
By comparison, for buy and hold here in Chicago we are looking at I am getting 12 cap. If we are buying and renovating to hold for rental we are looking at 20+ cap.
B: You could still present it to your investor, though you should remember that every deal every interaction you have with an investor they are continuously building their perception of you.
If you present a plan of this property, and write a letter about why you think this property is worth this much and that you are confident that this is a good deal, while providing comps and a detailed proforma and cash flow model, then it should be okay! If you present a plan you are not confident of, then it just makes you look like you don't know what you are doing, and it will make you look bad. If you can look in your investors eye and tell them its a good deal then go for it.
Just a thought - you are trying to wholesale properties that are essentially at retail prices. You should look for bigger discounts such as in not great neighbhorhoods or distressed homes.
Good luck!