Oh man that does not look too good, you almost always see black oil from the PCV Valve blowback caked up inside of the UIM, but that stuff has that rusty color that you really do not want to see.
Have you looked at the radiator, and oil caps?
If so what do they look like around where the rubber gasket/rings that are inside of them?
How about the oil dipstick, does the oil have a normal looking color to it?
It is hard to tell for sure where the leak started, but I am betting the EGR port on the old UIM had warped, and allowed coolant to leak internally.
With the UIM, I am pretty sure they just took existing units and beefed up them up a bit, because the one I bought was supposed to be redesigned, but it did not have a really current year date stamped onto the top of the UIM, instead it had some numbers grinded away from it, I'll try to get a pic of mine when I get some time, I have a lot on my plate at the moment.
There are 3 sets of numbers on the UIM, the right side will have the years on it, with an arrow pointing to the year it was made, in the middle you should see a day of the year stamp, showing the day of the year it was made, and the left side you should see a month of the year stamped onto it, I am pretty sure if the year stamped one is grinded off, then you have a redesigned one, if not it is most likely an old one, I could be wrong though..
As for cleaning that UIM, you may be able to get an old trashcan, fill it with some water and a good degreaser like purple power, even dish soap if that is all you have, it will need to soak for a while.
After you get it clean examine around where all gaskets go after the gaskets have been removed, if you see any warping I'd get a new UIM.
As bad as that LIM looks it will need to be cleaned out as well, you may even want to use some kind of brush to help clean out the intake runners.
And from what I can see in the pictures the LIM Gasket looks like the plastic framed one.
If possible I'd try to do a compression test on all cylinders, to get an idea if any damage has already been done to the rings, and to see the overall health of the motor, usually you'd want to do it with the motor a bit warm, but you can still get fairly accurate results with it cold.
After doing a dry test on the cylinders, squirt a few drops of clean motor oil into them, and retest, then compare the numbers on each.
If you do so I can help you understand the dry/wet compression number results.
Once the job is done I'd run it for a little bit, say around 100 miles or so, and then change the oil again.
Another tip for the LIM, when you remove those LIM Bolts try to get the threads as clean as possible, and when you put them back be sure to use thread sealant, and not lock-tite, you do not want the oil wicking up the bolts and starting to leak.
In case you get the UIM clean, and it looks reusable when inspected, let me get you the part numbers you need for the gaskets.
The TB Gasket I suggest is a bit more costly, but a much better choice than the orange ones, the Dorman UIM Gasket Kit has a blue one, it may not be as good as the black one, but should work fine, I would recommend the AC Delco Plenum/Throttle Body set, but it does not come with the reduced diameter EGR Stovepipe.
This Dorman Kit comes with the UIM gasket, throttle body gasket, EGR Gasket, coolant/water bypass gasket (not needed unless you remove the cover from that bypass, it is on the right side of the LIM), the PCV Valve Gasket, as well as a new thermostat and thermostat gasket.
It also comes with fuel injector o-rings, which is good because the LIM Gasket kit only provides new ones for the lower half of the injectors.
DORMAN Part # 615207 33.79 on RockAuto.
I'll go over my response after I have a little more coffee, had a long day yesterday and slept the day away today, so I am still half asleep.