Is communal remembrance (dhikr) permissible, and is it valid to perform remembrance in the manner described, involving closing one's eyes, turning off the lights, and adhering to specific numbers as directed by a shaykh?

The remembrance of Allah Almighty and gathering for it are among the best acts of drawing near to Him. Allah Almighty says: "And the men who remember Allah often and the women who do so - for them Allah has prepared forgiveness and a great reward." However, congregational remembrance (dhikr) is an innovated bid'ah that should be avoided, especially the described manner, as it was not reported from the Prophet (peace be upon him) or his Companions. We recommend the book "Al-I'tisam" by Al-Shatibi to distinguish the Sunnah from bid'ah.