Looks like I dodged a bullet on oil/water intermix
 

I had some significant amounts of oil in the water - no water in the oil. Unfortunately, these intermix incidents are not rare in our cars, and they are usually either the oil cooler (cheap and easy to fix) or a cracked cylinder head (difficult and very expensive to fix). I decided to swap out the oil cooler, which with the cooler and o-rings cost me a total of about $140 and took all of about 1 hour to change. The multiple cooling system flushes took far longer than the oil cooler swap.

Amazingly, when I went to remove the old oil cooler, I found three of the four mounting bolts loose, to the point that I was a able to remove them with my fingers without the use of a wrench.

I flushed the system out repeatedly until all the water was clear. I then put in distilled water with Prestone flush/oil degreaser. I've run the car with that in there for about one hour so far, driving the car the whole time. So far no sign of any oil in the water. I would have absolutely have seen oil by now before. I'm keeping my fingers crossed. Once confident that the problem is gone, I'll flush with clean distilled water twice more and then add the pink coolant.

Prestone sells a product that you are supposed to use after using their degreaser, it neutralizes the harsh, etching properties that the degreaser has on the aluminum engines.

I don't remember if you add it to the coolant, or you use and flush it prior to, it will only cost you something like $7 or so

Hopefully it is your solution.
Last year with preventative WP and Thermo change along with flush and new Pink stuff, I also included changing the 'O' rings as part of that. The old were flattened to sum degree.
But after reading about your bolts, I need to go back and check their tightness.

Thanks for the Light bulb moment.