All regarding your tax questions:
My husband claimed me as a dependent on his tax return for 2013. I just landed at the end of December, but it wasn't a matter of needing to be landed. If your spouse has a SIN, even a temporary one, then use that number for filing taxes. If your spouse does NOT have a SIN, then contact CRA and they will give you a temporary number that you can use for filing taxes including your spouse. Whether or not they are landed is irrelevant for tax purposes.
If you can afford to have a tax specialist do your taxes, then by all means use them. My husband used them and I have NO IDEA how tax law works in Canada, but they were able to transfer over some of the retirement income to me and do return under my name which netted use another 2k return that we otherwise wouldn't have received. Yes, it is apparently all legal, and no it does not require me to now file a US income tax return because it is not taxable. *shrugging* You know what, I have ABSOLUTELY NO IDEA what this tax accountant did, however it's above board so if you can afford a tax accountant, do it. LOL
*goes wandering off to read some on Canadian Tax Law*