I wish you categorized you're post in a few sub sections to make it easier to read, but thanks for your contribution for sure!
Regarding factory engine oil help gauge, I know for a fact now that it's fake. The sensor is real, but the reported engine oil temp does not use its readings to come up with the oil temp number displayed. Yes, you read that right. In fact, just go ahead and disconnect that oil temp sensor, do a test drive, and enjoy your fake oil temp readings being fed to you despite having that sensor disconnected! Long story short, having a real temp sensor does not prove that readings are not fake. Very weird, I know. It seems that sensor is rather used for engine oil level warning and engine protection mode at very high engine oil temps.
Check this out for more reading on this:
http://www.camaro5.com/forums/showthread.php?t=381050