This was my guess for the spirits list, which I posted in the Kazuya thread:
- Kazuya (two fighter spirits, since that's usually how it works when a character has a full alternate costume - though Sephiroth was an exception, and Zombie and Enderman are normal spirits, so I'm not 100% sure)
- Heihachi
- Jin (these two seem obvious, since it seems like they'd be in the running for playable character status)
- Nina Williams
- Paul Phoenix
- Yoshimitsu (much like Heihachi, those three have been in every Tekken game, so I feel like they'll get spirits here as well)
- King
- Kuma (while they've technically been replaced between Tekken 2 and 3, some version of Kuma and King have been in every Tekken game)
- Jun Kazama (she has ties to Kazuya)
- some form of Jack
- one of the Laws (Marshall or Forest - looking at their lists of appearances, I'd guess Marshall)
- either Michelle Chang or Julia Chang (I'm guessing that they're going to include the Tekken 1 starting roster or at least their substitutes)
- Lee Chaolan
- Anna Williams
- Lei Wulong
- Devil (Tekken) (I'm guessing this one would be the legend spirit)
Even then, I felt like I missed plenty of characters - Eddy Gordo, Asuka, Lili, Alisa Bosconovitch, Mokujin, Jinpachi Mishima, Ogre... That's why part of me is hoping that Tekken gets three pages worth of spirits (more than 16) - there are a ton of characters in the series.
Out of that list, I feel the most confident about the characters that I listed between Heihachi and Kuma, including those two. (all of them but Jin have been in every Tekken game in some form, and Jin's one of the characters who would be in the running for the playable Tekken character in Smash)