You really need more information to answer these questions. Usually the company does what they are going to do, and then you need to find out the best way to reduce the taxes.
As mentioned, while they would not have to deal with the CPP/EI, your contributions will double as a consultant, so that's not a good thing since you will be paying both portions. Yes, you will be able to claim deductions, but not everyone has a lot of deductions, so it depends on your income, personal situation, and expenses directly related to the business to see if you will come out ahead.
Contractors have most of the same deductions available to corporations, so the question is whether it will be worth the incorporation fees, and fees in excess of $1000 per year to maintain it, in addition to your personal return. In the end your corporation has to pay you as either an employee, through dividends, or a consultant? It really only helps if you are planning on keeping lots of your pay in the corporation, or have a very large income. The benefit also varies according to province.
Only US citizens and green card holders are required to pay tax on income earned outside the USA. So, it is likely that you can resolve yourself of US tax and filing requirements once your move to Canada. That might be a large benefit, depending on your intentions later in life.
