Depending on your income level, family status, immigration status, and location of residence, there are various benefits that you may qualify for including:
No, Canada does not allow joint filing so both you and your spouse will need to file a tax return if required.
While a tax return may not be required if your spouse has no income, we would generally recommend your spouse file a Canadian tax return starting the first tax year your spouse is in Canada. This will allow CRA to assess any tax benefits that you/your spouse may be eligible for.
If you make cash donations to a Registered Charity in Canada you can claim a credit on your tax return.
If you make donations to foreign charities, they are generally not eligible for a credit in Canada with two major exceptions:
If you make non-cash donations, they are generally not eligible for a credit.
There are a number of exceptions and specific cases, you can find more information here.
Typically, we see charitable donations, certain out of pocket medical expenses (not covered by insurance) in excess of a certain threshold, RRSP contributions, professional memberships, etc. More information can be found here.