If a user self-frezes, do you still have to wait a year before you can use that username?

Yes though I think frozen is 10 months and regular inactivity is 12, just remember about 3(may want to double check) weeks before it's due to be taken it pops up with a banner saying "this username will be cleared (or whatever the terming is) on x date at 3pm"

Accounts get marked for inactivity after 10 months, with the notice that they'll be cleared on xyz date. Frozen accounts always have the date listed from the day they're frozen, but you will still need to wait a year to use the user/pet names