You acquire tokens based on how much LP is spent to play a song.
You acquire tokens by playing other songs that use LP and collect them from notes that have the token symbol. There is also a ladder system which rewards you different items based on how high you are on the leaderboard for an event. Once you acquire a certain amount of event points you will be given various rewards including loveca, friend points, gold and idol cards (N, Exp Cards and SR).
Playing an event song and earning tokens gives you event points. Token events are when players gather tokens in order to play an event song. Loveca can be purchased with real money and is the way the developer makes money from this game. Alternatively, you can use 50 loveca to recruit 11 rare or better cards. You can use 5 loveca to recruit one rare or better card. Loveca is used to recruit rare or better idols on the recruitment page or to fill up your LP gauge.
Ruby might have a twist on Yoshiko's usual side-bun. I noticed that Yoshiko's side ponytail looked like Ruby's usual pigtails. There are the horns, from the 2nd years' outfit. Most likely Riko, judging by the shadow in the clean version. I'm pretty sure the aeroplanes were Rin's image colour. I'm not sure about this one, but I saw the background leaked somewhere. The legs in the background are suspiciously like hers, and I don't think that's the 3rd or 2nd years' dress. I know I guessed her before, but I'm guessing it's Rin. She'd be adorable in a frilly dress playing with a toy aeroplane, and hopefully, the artists think that, too. There's no way to tell what it will be just by looking at the image with SSR's, but I think it's Rin. My guess is Mari, just because she loves rock. Here's what I got: Possibilities are Hanamaru and Mari. I worked out the possibilities for the unpaired SSR and UR partners.