1)
テレビがありません is not wrong, but テレビをもっていません is more close to the nuance of "to own".
2)
ある can't be used for animated things.
3)
The particle differs depending on the verb or the function of "the movie", so に can be both correct and wrong.
4)
I prefer 授業[じゅぎょう] for the translation of "class". クラス sounds like "classroom" (at least to me).
7)
same as #1