It would describe it as bright appliance white.
No this product is made of extruded aluminum.
This product does not lend itself to being cut. If you need 5.5' you would be best served using a 5' and the appropriate telecscoping accessories for your installation type.
Yes you can. I had to do this in my home as the pipes come through the wall not the floor. However I had to us a hole saw and a hacksaw as the aluminum is quite thick. Snips would not work.