Thanks @seehat_inder . My mother has a super visa valid till 2024, but cannot stay longer than 2 years continuous in Canada. Guess I can use 6 months as a safe input as she is going back within that time anyhow .1) Canada
2) Her visit permit expiry date. If there is none the usually visitor permit is for 6 months.
3) I guess, biometric can be done in any country.
thanks...