Deleted Role: Sofia Vergara flew to Paris to film a tiny cameo, reprising her role of Odile Anjelou from the previous installment but ultimately for story clarity the scene was omitted as to not muddle things up a bit.
Not as much missing but altered for the scene with Hackus spazzing out:
Hackus does spaz like Taz the Tasmanian Devil but, although he does burp, it's in a different scene.
In the actual movie, Azrael’s dangling from a makeshift net like a caught fish whereas he’s missing in the trailer.
Another altered scene is in the trailer, Gargamel says “Naughties attack!” to which Vexy pushes Hackus into some body of water. That doesn’t exactly happen in the movie.
As mentioned under Never Trust a Trailer, Gutsy and some Smurf are shown swirling in a vortex along with Papa and Vanity. Though the scene does happen after the Smurf Essence breaks from the container but it's Smurf turned Hackus and Vexy swirling around in the substance along with everybody else (Papa, Smurfette, Vanity, Clumsy, Grouchy, Azrael, Gargamel, Patrick and Victor).
The Other Darrin: In the Italian dub Papa Smurf is voiced by Bruno Alessandro, since his voice actor from the first movie, Gianni Musy, died in the meanwhile.
along with her niece.