Sorry to hear you still have the blip, Searcherrr, it must have been a big disappointment.
The resistance test results look good at first glance - I don't see anything to worry about, but I'll take a closer look at them.
Test 1: 0.554 kilohms (554 ohms) from VPWR to ground - that's fine - see my comments for test 3.
Test 2: Conventional multimeters aren't capable of measuring 0.4 milli-ohms, so I'll assume that 0.4m (lowercase, so milli) should be 0.4M (uppercase, so mega). That would give readings of 4.9 kilohms (4,900 ohms) to 0.4 megohms (400,000 ohms) from VPWR at C128 to battery positive terminal. VPWR doesn't get 12V directly from the battery; instead it takes it from the switched contacts of the PCM Power Relay, which was switched off at the time. Therefore there was no direct path between VPWR and battery positive, so what you have measured is likely an internal resistance within the PCM between the VPWR inputs on pins 71 & 97, and the B+ keep-alive power input (KAPWR) to the PCM on pin 55, which is indeed connected to battery positive at all times, to preserve the PCM's volatile RAM data. Without an internal schematic for the PCM, what that path actually consists of is anybody's guess, but it's safe to say it won't be purely resistive - there is probably considerable circuitry between the two points, and that's what you see on the meter but you can't really draw any conclusions from it. The variation in resistance would have been some of the PCM's capacitors taking a charge via the meter's probes. Having said all of that though, testing resistance between those two points is fairly pointless and not worth repeating.
Test 3: 0.554 kilohms (554 ohms) from VPWR to battery negative cable with battery disconnected. The battery negative cable is at the same potential, electrically speaking, as vehicle ground, so this is the same measurement which you already did in test 1 - hence the same result, so these comments also apply to test 1. Just to explain where that reading of 554 ohms comes from, imagine that you're working on a lighting circuit and you're testing resistance at the 12V feed into a bulb. The battery negative cable is disconnected. Now when you put the meter's positive probe onto the wire which feeds the bulb, and the meter's common probe onto a ground point, you are effectively measuring the resistance through the bulb, eh, so you will see the lamp's filament resistance with, perhaps, other paths in parallel depending on how the circuit is configured. So when you put the meter's postive probe onto VPWR and the common lead to ground, you're measuring the resistance through all the components between the two points, which by the way is many. If you look at the wiring diagram and follow VPWR back to its splice point, you'll see it branches off in many directions. Follow it further and you'll see it branch again, and then I think it branches again, because it feeds a whole host of ignition and emissions systems control devices and sensors. The easy way to visualise that is as a bunch of resistors connected in parallel between VPWR and ground, and you have measured the effective parallel resistance between the two points. Once again, having said all that, the actual resistance figure which has been obtained tells us little except that you don't have a short-circuit to ground, so in that sense it was worthwhile.
Test 4: Resistances from VPWR at C128 to each terminal of the ECT sensor. I shouldn't pay too much attention to those readings. The light green/red wire connects to PCM pin 38, and there's no way of knowing what resistance might be expected between there and VPWR, and then the ECT's grey/red wire branches off all over the place, with series resistances of various sensors along the way, likely with some of them effectively in parallel, thus forming an intricate little series-parallel network, so without knowing the resistance values of all the components, it's not possible to know what resistance might be expected between that point and VPWR, and even if we did know the values, there would still be paths within the PCM for which we could not account, so it really is almost impossible to interpret.
So that all looks good to me, and there's nothing that I would be concerned about.
VPWR is not shorted to ground. If it was and if you applied 12V from the battery then there would be a massive current flow - maybe many hundreds of amps depending on the exact resistance. In fact though you have 554 ohms between VPWR and ground, and if 12V is applied then the current would be 12V divided by 554 ohms, which equals 0.0216 amps - in other words, a mere 21.6 milliamps. That's about the same tiny current which flows through a regular old-fashioned low-intensity LED. It's hardly any current at all. It isn't a short-circuit.