Hey Capt' i don't think you will be able to change out the front shaft from an Np435 for a C-6 shaft. They are different lengths cause' the transmissions are different lengths.
Your back shaft will be the same length, but not the front one.
As far as the carrier bearing goes.
I break off as much of the bearing as i can. IE: the rubber, and the outer race. Then i put a cut-off wheel on my 4 inch grinder, and cut the inner race.
VERY carefully cut through the inner race. I go until i'm pretty uncomfortable about going any further. Then i split the inner race with a cold chisel, and slide it off the shaft.
I clean up the shaft with 250 grit sandpaper, then finish it with emery cloth.
Winter is my favorite time to change these.
Put the shaft outside, temps need to be near zero. Otherwise put it in your chest freezer overnight. Anyway you do it, get that sucker COLD!!!
I usually put the complete carrier bearing assembly under a heat lamp, not close enough to melt anything, just close enough to get everything (including the inner race) nice and WARM.
I then grab the shaft, block it upright somewhere, grab the bearing and slide it down onto the shaft. It may need some ambition to make it the last inch. I use a piece of water pipe (that has the same OD as the inner race on the bearing), like a slide hammer and drive it the rest of the way on.
I have done dozens of them like this. Not just bumpside drive shafts either. Anything that has a carrier bearing.
The biggest trick i have found is timing. Keep the shaft as cold as long as you can, and the bearing as warm as you can. When you put them together, keep moving, don't stop to think about it. Time is your enemy here. The longer it takes, the warmer the shaft gets, the colder the bearing gets, the closer in diameter they get.
Otherwise, take it to a shop and have them press it on.
Just my
Good luck,
Two-bit
S
I don't have a torch 
