i think the point is, banning tiktok just means influence can move to these other platforms via other means (troll farms etc), it doesn't solve the issue (unless you want to ban twitter et. al)
There’s a distinction between adversaries trying to cause trouble within American companies and a foreign hostile government effectively owning the company and dictating policy in its own interests.
Probably? I think that was one of the options iirc (ownership by an American company via a sale), but I don't really know enough about the specifics to have a strong position on the implementation.