If we buy a champion that we already own, do we get a permanent champion / shard in the loot list so we can use to upgrade the mastery tier? If not then I think Riot should at the very least implement this otherwise it's just a plain skin sale...
Nope. Basically just a skin sale somewhat optimized around you that can have legacy content and much larger than usual sales.
You can get the champion with it, but you pay RP cost for the champion if you do.
If the shop is recommending champion permanent + skin bundles of champions you already own, there's been a SNAFU somewhere and you should probably submit a support ticket about it. It shouldn't be giving you champion bundles if you owned the champion before the My Shop started.
