They used to be available only after you did the showcase, but now I’m getting email invites for them even though on the main screen they are still locked. Have they been opened up, because I think that would be an excellent move. I can play spotlight evens only though the invites atm (or is it a bug?)
Get through the ‘career’ as quickly as possible and don’t worry about getting platinum as you can redo them to improve. You have to be finished with career to go to showcase. The reason you are getting invites is that new showcases are loaded every few weeks and old ones are discontinued. This means you are losing out on opportunities to gain badges as once the showcase is closed it cannot be done.
I missed two of the original showcases because of this. There are now either 4 or 6 that are closed.