Good day to all! Need some advice from experienced travellers here.

1) My friend has already booked her economy tix (upgradable) SIN-LHR. I'm thinking of joining her on her trip by redeeming a J tix using my own miles and is it possible to upgrade her to a J seat using my miles as well? How do i go about it?
​​​​​​Do i add her as my redemption nominee and will i be able to access her booking through my account? Or i've to call in?

2) She has a flight to Vancouver on Air Canada (*A partner). Can i upgrade her to business using my krisflyer miles too? Will be joining her as well.

​​​​​​​Thanks in advance!