Holmes108 Hey! Great questions! As of right now at launch there are unfortunately no variations of Stream+ tiers in order to upgrade one particular streaming service within, but our team is definitely aware of that and looking into options for the future.
As for cancelling the Stream+ package, you'd obviously no longer have access to the streaming accounts through TELUS and subscriptions may automatically renew with the streaming service provider if your previous method of payment is still on that account and up to date. Otherwise, you may have to update your payment info with them to resume service as before. With respect to billing, you'd be charged a prorated amount starting from the first day of your billing cycle up until the day you stopped the service.
The process to do so is here and should you want to see the individual services' support pages:
Netflix
discovery+
Apple TV+ customers will get an email automatically from Apple notifying them that their previous Apple TV+ plan will be resumed and billed by them.
Hope that helps! Let us know if you have any other questions!