When signing up to Apple One Premier, are the current individual subscriptions I have that are included in Apple One Premier automatically rolled into the One?

See the following from Bundle Apple subscriptions with Apple One - Apple Support

Apple One includes a free 1-month trial for services that you don’t already have. After your free trial, services that you previously subscribed to are automatically included in Apple One.

Also, if you already had an What happens to your iCloud storage plan when you sign up for Apple One - Apple Supportupgraded iCloud storage plan, see the information in: