Personal headcanon that Picket and the Swooping Evil are with Newt for a reason. To get out of trouble when he can't use a wand.
It might have started with Picket having attachment issues but after serveral times the little bowtruckle got him out of a bind, Newt is protesting far less when Picket wants to stay with him.
The Swooping Evil? Most people don't even know what that is. Easy to gain an advantage as seen in the movie.
Theseus thinks it hilarious and approves heartily.