What is the ruling on a congregational prayer where the voice of the Imam was cut off during the Friday prayer, so one of the congregants completed the prayer for them? And what is the ruling if no one came forward to complete the prayer for them? And do they complete it individually as Dhuhr or as Jumu'ah?

The Friday prayer is valid for whoever catches one rak'ah of it, even if each person prays the last rak'ah by himself if no one leads them, by analogy with the pre-empted person who makes up what he missed, based on the general statement of the Prophet, peace and blessings be upon him: "Whoever catches one rak'ah of the prayer has caught the prayer."