light-le
1. If you have shown work experience for labor, you need to provide work experience letters. But other than that I do not think you need any new documentation.
2. There are more changes with CP now. There is routing of application change, which might delay the process by another month or so,... but I still think CP is the way to go! The only thing is, you need to travel to india for interview. If you are the primary beneficiary, you need to go to chennai consulate for interview.
3. As of now, CP is faster.
hope this helps.