So any legit leaks happen as far as we can tell?
No, and don't expect anytime soon
Usually, the most credible and correct rumours/claims have appeared in the weekend or week before Nintnedo's E3 i.e.
-DKCR E3 2010 IGN
-Goldeneye E3 2010 (although this was third party)
-The sneaky hints of the Nintendo press badges and lanyards with the 4 playable Super Mario 3D World characters and Donkey/Diddy Kong (the 3D World was also hinted at the 'come play with us poster when the first E3 Direct was revealed')
I think this year we might get leaks of these NFC figurines, just because hardware has usually been the most leaked Nintendo details from E3, and this NFC/NFP platform is a form of a new cross-strategy.
Even then, we have had plenty of wrong/misinformed claims form journalists i.e. claims of Retro working on a new IP/franchise last year. It also helps that Nintendo usually inform some journalist outlets on the weekend or just before E3 of the games/console. Geoff keighley and I think another website were shown the Wii U, IGN Nintendo knew of the games on the weekend before E3 last year.