Considering BM naruto couldn't even tackle Obito without the help of Kakashi Bee and Gai yeah, Sasuke wouldn't fair any better. So yup
Obito >> all Sasuke Forms.
EDIT: And Obito's mokuton use is cannon not filler.
Sasuke would win. Underestimating him.
Not without Kakashi being present. all of Sasuke's attacks including MS attacks are gonna go right through Obito.
Sasuke strong, but Obito is not going to get beaten without another Kamui user present (Kakashi) to make his attacks connect. If Kakashi is present, then yes Sasuke can win.