One of the most shocking announcements ever!
http://www.nintendoworldreport.com/news/35128
Luigi has been confirmed as a playable character in both the Wii U and 3DS versions of Super Smash Bros.
Luigi's inclusion in the games should come as no surprise to Smash Bros. fans as the eternal understudy has appeared in every iteration of the series.
This news comes from today's Nintendo Direct presentation and was revealed as part of The Year of Luigi celebration.
I don't think Luigi was ever in danger. My biggest worries were Ness and Lucas, since their franchise isn't as well known. Hopefully, the NA VC release can keep them. Ike might get swapped for another FE character. Lucario is a maybe. Snake and Sonic might need their respective owners to ask for their inclusion, and Snake hasn't really been popping up on Nintendo systems lately.
I'm sure Sega wants Sonic to be in, so they'll ask and Sakurai will oblige. It's Snake I'm not so sure about. Will the "3rd parties have to ask" rule still be in play for returns or will there be some negotiations involved? Nintendo would probably want something in return for Snake's inclusion eventhough he was so popular.