Welp, I noticed that I was 70 coins away from the final Platinum, and though I imagine they'll just try to foist off Game and Wario and the like again, I figured I'd take the plunge and go elite. I tried the free 3DS stuff on the guide posted here, but unfortunately none of them are giving points or surveys anymore. I bought a few cheap eShop and VC games to nickel and dime my way up, but only Gunman Clive gave a 5 point survey (and no points for the game itself). Edge isn't even showing up as registered software for some reason.
Clock ticking, I took a break a few hours ago to drop into the Gamestop at Atlantic Center in Brooklyn to pick up a few new 3DS games I was planning on getting eventually anyway to push me over the edge. I opened up Kirby Triple Deluxe and Fire Emblem Awakening at home to find no codes. Research then enlightened me to the fact that newer pressings of eligible titles no longer give coins, and it's a crapshoot as to whether anything on a shelf is pre-discontinuation or not. Doh! **** me for not looking into this ahead of time, I suppose, though a "used" copy of Rhythm Heaven Fever I bought a few months ago still had a working code.
Anyhow, I just bought $10 worth of fire sale Club Nintendo cards on eBay to put top myself off. Here's hoping the seller follows through and actually emails me the codes within the next few days.