1st - it's normal for the engine to rise once the engine (and fan(s)) are shut down there's a lot of 'soaked heat' in there still that has to dissipate over time. It's the reason some newer cars actually run the electric fan(s) for a length of time after you shut the vehicle down.
So your problem seems to be from lack of heat transfer from the radiator to surrounding air to allow proper cooling performance.
This could be due to;
* need for air circulation from the fan(s) system
* problem with radiator sizing or heat transfer
Is there a reason you don't have the fan system on an automatic temperature controlled circuit?
Also, and I know this is a weird question, are you sure the thermostat is actually the rating stated and it is installed correctly?
Did you notice if it had a Circulation Hole in the unit to allow a small by-pass of coolant to help with warm-up and prevent any air-lock issues? If not, you can drill a small hole.
I have been drilling 1~2 1/8" or so holes in every thermostat I've installed for something over 40+ years now ...
Will look like this -
You don't have to go overboard like the Ford guys do
I would also encourage you to allow the vehicle to get to operating temp and then raise the throttle while observing the Lower hose - you can usually see signs of it starting to collapse at mid-range throttle speeds.
Last quick stop would be to stop by a local radiator shop and have them run a quick test of the system for combustion gasses.
You can also rent the kit from AutoZoned and other parts stores and do it at home yourself
Scotty here can show you how -
Oh, and I wouldn't be worried about oil pressure or bearings at this point.
If a bearing was really bad you'd hear it and there wouldn't be enough 'friction' to heat the oil - or you'd REALLY hear it ...
A drop in pressure is normal as engine temp. increases.