Convert to Apple One Premier

Here’s my current situation...

Prepaid 1yr subscriptions to Apple Music and Apple TV+

Monthly subscriptions to News+ and iCloud+ (2TB)

If I wish to combine these into a single Apple One Premier subscription how will that work? Will I get prorated refunds on my prepaid 1yr subscriptions? Will the remainder of the prepaid subscriptions gp toward the monthly premiums of Apple One Premier?

Might anyone who has done this explain how it went down?