I did actually find it on a Japanese wiki, how to set different co-ords. It's under the options menu (second tab, final option (set it to する)), but you can't use it until after clearing the Idol Extreme at least once. Dunno how to set it for S4U but that should allow it easily for produce mode at least.
I've been going a bit slower than Setsuna, but I'm in Y3 Spring now, just barely winning the C3 all star live last winter. Added Yukiho to the line-up. Also got a revival on Ready, though now that leaves me wondering how you get the Gold status since that one gets an achievement... Gold and Break status aren't explained very well in the manual but I can't seem to find them on the two Japanese wikis either.
As an aside, most of the base work I had to do to get the english wiki going is finished. I have to fill in charts more and such, but the initial tediousness is finished. There's a lot more I want to add though.
I'm back and trying to recover a bit before I go back into the breech.
I've managed to get Torani ni... to go Gold - I think it requires you to use a song to break a certain number of sales or more likely gather a certain number of fans. I haven't seen a song get removed from gold, either.
In my case, since Torani ni... is one of the two FES songs of choice (yes, it's that overpowered) I think I spammed it like 100 times total. Not sure if it's a use count or just a total number of fans collected (I wouldn't be surprised if it was the latter though) using the song.
So that explains what the last option is. Well, I can find out in a few minutes. Having 9 A1s with nothing to do has its advantages.
Oh, almost forgot. Does anyone know of the exact stage count in OfA? I need the data to compare to the file.