The 3 key features that most people I know who still use Facebook are Photo Sharing, Event Organizing, and Messaging. The things you listed do one or two, but I don't think any of them do all 3.
If company A is selling hot dogs and ice cream, and B is selling hot dogs and C is selling ice cream, does that mean A has no competitors?
WeChat does all three of those, plus payments and food ordering. Basically everything Facebook wishes they could do, WeChat does it for about 1B people.
WeChat doesn't have a significant presence in Western markets, and Facebook doesn't have a significant presence in China. They don't really compete with each other, even though they provide a lot of the same features.
I'm pretty sure WeChat does all 3...
By that standard you could claim that the Honda Civic has no competitors because no other vehicle has its particular combination of features.