The things that were replaced sounded like they needed to be replaced, well all but possibly the EGR.
If the Dex Cool was let go for too long without servicing it, and air was let get in, and stay in the system a while, or Non Dex Cool AF was mixed with the Dex, then it can/will get cruddy and nasty, and cause all of the things listed to need to be replaced.
So I don't think those things were OK, if they had been replaced by the owner and not a mechanic, then the cost really would not have been much, the most costly part would be the radiator..
I'd do what Tech II suggested with the IAC and TB first.
Then considering what all was mentioned that they fixed, and the reasoning for fixing it, I'd have the cylinders all checked for compression, if the compression is good then I'd do the UIM/LIM job.
You can get a compression tool on loan from AutoZOne I think it is..
The cylinders should be fine since it does not sound like the motor got any coolant into its cylinders, but a compression test would help verify all cylinder are in good shape.
If it still shuts off after all of that then the ICM would be my guess, when the ICM starts to go bad heat-soak can cause the car to stall.
Oh yeah, another thing to check, be sure the tip to the MAF Sensor is not coming off of the sensor, it can come off and spin in the TB'* MAF bore, and that will occasionally cause the car to run poorly upon start up, and could cause issues if the tip got stuck blocking off the throttle body MAF bore...
If the tip easily comes off easily then I'd remove it and see is the car still stalls, if it doesn't replace the MAF eventually.
I had an issue with that happening, and the MAF still ran the same with the tip removed, so there is no rush to replace it if that is an issue..
2006 Pontiac Grand Prix GT with SC
1996 Buick Park Ave NA