Can this longer
thermocouple's ends be cut off and be replaced with the same type of U
interface that the current one uses?

Short answer is Yes, they *can* be cut off. More on this later. It seems like a lot of work for a dubious outcome.
But first: Verify that the extended TC device will provide accurate information to that device. This is not certain.
And also: Unless the entire environment is under difficult conditions, what about using conventional wire to extend the shorter probe?
Again, verify that such an extension will still allow accurate information to get to the device.
And, lastly, why not adapt to that plug. Use a couple of appropriately sized insulated push-on connectors to short spade-lugged jumpers. This being after you verify that it provides accurate information. Even better, if the spacing is correct, use crimp-on spade lugs directly onto the plug tines.

Remember, this venue exists in order to provide the most difficult and complex solutions to otherwise simple problems in the most obscure and irretrievably awkward way.

Peter Wieck
Melrose Park, PA