You can cut the excess off, I would not grind it. Take the axles to a shop that has a saw to properly cut them. Then taper the end of the splines a little to match what they look like now. You will probably have to do a little clean up on the axle ends.
Double and triple and quadruple check your measurements before doing so. You can't put it back if you take off too much.
I would not shim the bearing end.
