The H-1B is subject to a lottery so that's not an option. The L-2 would give you unrestricted work authorization but would depend on your spouse maintaining her L-1 job. The TN is company-specific so you would be tied to the company. Given all this, my recommendation would be to get the L-2 (as a Canadian, this is super simple and fast) and then if for some reason your wife loses or wants to leave her job, switch to TN at that time.