The tag deadpool seems to about the character, and while it's not explicit, I would assume about the comic character mainly.
The tag deadpool-2016 says:
Use this tag for questions related to the 2016 Deadpool movie. Use [deadpool] for general questions about the character or the franchise.
So it's possible to only ask about the movie, or not want 'general' answers about the character.
So no I don't think would be good to require every deadpool-2016 question to require the deadpool tag.
For instance:
What are the names in the dead pool in Deadpool?
Has no relation to the character himself.
In conclusion, most would have both, but not as a rule. Only because you'd imagine a question about his movie would involve the main guy himself.