The 550 fan motor in the 01-07 edge chassis is well known to have overheating issues. This is caused by two things: limited ventilation in the Edge chassis hood and belly pan to bring in cold air into the engine bay for the fan cooled motor, and lean jetting in the throttle midrange. These motors didn't like to be run at a steady 40mph for a long time, and is the reason you will find so many of these motors that need a top end rebuild.
I am not familiar with there being an oiling issue for the 550 fan, but that doesn't mean there isn't one. All the 550 fan motors I have come across never had issues with the crank/bottom end.
Best way to tell if you have had engine damage is to do a compression test.