You won't need any parts unless the rubber hangers are broken.

You don't need to remove the O2 sensor. Simply raise the passenger side front carpet, disconnect the connectors and push them through the hole in the driveshaft tunnel.

Remove the four nuts at the manifold, the hanger at the transmission paying close attention to the orientation of the rubber bushings, and then unhook the rubber hangers at the rear. For your purposes, you probably won't need to unhook the rear hangers since you're just trying to get it out of the way for the idler arm bolt.

Upon reassembly, put antisieze on the manifold bolts if you want.

That said, I've been there and done that. It is much simpler to just cut the bolt. In order to get all the slack out of your new idler arm bushings you will have to tighten the SNOT out of the idler arm bolt. For that reason, there is absolutely no danger, when putting the new bolt up from the bottom, of it coming loose. That is Steve Brothertons method, and if it is good enough for him it is certainly good enough for me. I put my idler arm together that way a few years ago and it is still tight. I check it, along with many other things under the car, at every oil change.

Good luck,