NEed advice here on next steps. My oil pressure light came on on Xmas day on a highway, unable to pull over immediately, I proceeded to the side of the highway out of harms way. The motor died and I then was towed home.

I then towed the vehicle to our local Mitsubishi Dealer to request a professional opinion as the engine did not overheat, still plenty of oil in the motor, no head gasket blown. The dealership removed the tapyt cover and the oil sump cover and noticed some small iron filings. The dealership then informed me the motor had siezed and needed a complete replacement. I have worked on cars previously and failed to understand how they came to this conclusion as they did not remove big end bearings, cam shaft or remove plugs and I believe this to be shoddy work. This professional opinion must have taken them 10 mins to make without inspecting vehicle closely.

What are my next steps?

 

On a lift, you only need to pop a little plastic piece off to place a socket on the crank bolt and try to turn. No budge = Locked up

Lack of oil circulation would certainly do that and if shavings had blocked some of the oil journals, that would starve parts of the engine, leading to top end seizure. Since Mitsu didn't use dry sump on any of the Outlander engines, the bottom end would be splash and spray lubrication, so since you state there is still oil showing on the dipstick, it wouldn't make sense for the block to have seized. Hopefully you just have a frozen head and perhaps removing the timing belt will allow the crank to turn. Not that new heads are any fun to rebuild.

Just a guess from what you said. Pictures could help too