Looking to net 4 figures a month in cash flow with this unit - the goal is to close 7 more by the end of the year - let's see how it goes. 

I can pay for all my problems using the cash flow from my current rentals.

But we also like the idea of having the highest cash flow possible.

How will the partnership cash flow cover the HELOC payments if interest rates increase?

Based on what my real estate agent thinks that this quote will be, roughly, and the after repair value, it looks like I could buy this property in cash, spend a month or two fixing the damage, and then put a mortgage for roughly 1.6x what I paid for it and thus have a cash flowing property at a few hundred dollars per month and a little more money in my bank account ready for a down payment on the next deal.

You are looking at this through the lense of cash flow, don't forget you are also paying down the mortgage and might see some appreciation, so equity growth might be more than cash flow.

He was a realtor based in the Midwest (I think the greater Chicago area) and was talking about off vs. on market deals and the importance of choosing equity over cash flow. 

Obviously the answer is yes when it comes down to the cash flow, but I am particularly wondering if HCOL/high property tax areas are places you would cross off the list entirely.

First time investor, looking for cash flow.2.

Just ensure the agreement is clear and formalized.Pooling reserves across properties might make sense if you’re confident in your cash flow and other contingencies.