Just an update for anyone following this :
As of June 11th, Google has issued a fix that prevented users from changing their home address in Wallet if they had a Google Play balance.
We're pushing a fix for one of the issues that was preventing users from updating their Wallet home address. Starting today, having a Google Play balance should no longer prevent you from changing your Google Wallet home address.
I was able to re-subscribe to Google Music All-Access on the Canadian side, and also got the promo price of $7.99, which is good until June 30th.