Sure does play wide for a "number 10".
When he joined:
So basically the same as he plays for Parma, on the opposite wing.
Most likely Kulu will have to fill the right/center side of the field and try to play link dybala and cuadrado, while the rest will support Cr. I hope he plays as an hybrid winger/mezzala, because i think theres is where his strenghts are.
Ronaldo and Dybala should continue doing what they are doing.
To not tweak much the formation, it would be better just to improve the midfield and let the trio of Dybala cr and kulu do their thing.
If Kulu´s numbers are mostly on the wing, i dont know if it would be wise to reinvent the well with him. Just let him do what Berna doesnt and thats it.