Do extended & director's cut versions get released in theatres?
The only sensible answer is "sometimes".
Where movies are particularly popular or well received then studios sometimes release special versions to extend the cinema run (knowing that the extra expense is worth it).
For example, David Fincher's dark nightmare Seven which is particularly notable for its very dark (or chiaroscuro) cinematography proved popular enough to sustain a special edition release for cinemas on a contrast-enhancing film process that emphasised the effect of the dark scenes.
The Lord of the Rings trilogy also released the (even better) longer versions of the movies in cinemas but only after the success of the (already very long) originals had been established.
And various Blade Runner special editions were eventually released in cinemas but long after the original, not very successful, cinema release and only when the movie had proved a cult hit on video demonstrating that there was an audience for Ridley Scott's original version (the original release to cinemas was somewhat altered by the studio).