I still think that there is an issue with the 150 PSI of compression even if the 100 PSI cylinder is omitted from consideration. The ensuing overheating certainly did not help that 150 number.
My gut feeling is that this van may have had some issues from the prior owner.
What would I recommend as a quick diagnostic? The connection of a vacuum gauge. It’s quick, easy, and can reveal a lot about what’s going on inside of a running engine if the gauge is interpreted correctly.
It might be noted that certain 2012 Dodge and Chrysler mini-vans are under a Recall for engine problems due to debris in the block.
Getting through the murkiness of whether your van is included or not may be difficult but if covered the Recall states the engine will be replaced with a new one.
In a perfect world, this should have been sorted out from the start. Given the hectic pace and headaches of a service department it could well be that no one bothered to check as to whether it’s covered or not.