Since I had some X-ray spares on hand. I did some measurements.

The stock TRF418 C-hub is 11.9mm wide at the hinge pin point. The X-ray T3/T4 C-hub is 12.3mm wide at the hinge pin point. If shaven down, yes, it will fit in a TRF418 arm. Drive axle opening (for DCJ) is much larger than stock TRF418 C-hub so don't see any issues there.

Top to bottom of TRF418 steering knuckle is 21.6mm. Top to bottom of T3/T4 steering knuckle is 20.5mm. So you will need to shave the TRF418 steering knuckle shorter to fit the X-ray C-hub.

Height wise for the ballstud hole on top of the C-hub is very, very close. It would be very easy to retain almost the identical geometry.

Other interesting facts, stock TRF418 C-hub is 2.3 grams, X-Ray T3 C-hub is 3.3 grams.