If it's a solo or from a different line than Sudowoodo, then I expect it to be Grass/Ghost or Grass/Dark too. If an evolution of Sudowoodo then I expect it to be Rock/Dark. However Rock/Ghost would be cool to see, would get rid of Rock's weakness to Fighting.
Well looking at all the possibilities we can speculate how good this pokemon may be.
From a stand alone pokemon point of view
Grass/
Ghost- This typing is good in my opinion because the combination of Ghost and Grass neutralizes 2 types (Poison and Bug), resists 4 types, is immune to 2 and there is no 4x weakness. I think a weakness to 4 types isn't to bad when you have immunities.
Now to the offensive, Grass and Ghost has great attack coverage because theres not much you cant at least hit neutral. Lets not forget the kind of moves it could have, can you imagine a Ghost type that could pack Sleep powder or even yet Spore!(I doubt it would get Spore lol, but you get my point)
Grass/Dark- I don't like this combination, Dark hurts the typing more than helping it. The good news is that it get 2 new resistances and 1 immunity, the bad news is that it get one 4X weakness to bug and adds 1 more weakness to fighting, nobody likes 4x weakness to Bug specially when U-Turn exist.
Offensively is good since only Steel can resist you and you got sucker punch. You probably would get stat boosting moves like Nasty Plot but we don't know what this pokemon stat are yet.
Ill think about the Rock/Dark typing and Rock/Ghost typing later.
