There is no limit to the cash back you can earn for the standard 1.25 % rate and also there is no annual fee for supplementary cards. (creditwalk.ca)
I actually don't know the answer to that since I don't use supplementary cards. (moneywehave.com)
No charge for supplementary cards - If you're looking for a supplementary credit card, you can get one at no additional cost — an ideal option for extra cardholders. (lowestrates.ca)