Those who were not able to continue following the imaam in Friday prayers because the electricity was cut off

Praise be to Allah.

If the situation was as described by the questioner, then the prayer of all of them is valid, because whoever catches up with one rak’ah of Jumu’ah has prayed Jumu’ah, as it says in the saheeh hadeeth narrated from the Messenger of Allaah (peace and blessings of Allaah be upon him). If one of them had not stepped forward and they had each prayed the final rak’ah alone, that would have been OK, as in the case of one who joins the prayer in the second rak’ah with the imaam, then makes up the other rak’ah by himself – because of the general meaning of the hadeeth in which the Prophet (peace and blessings of Allaah be upon him) said: “Whoever catches up with one rak’ah has caught up with the prayer”. And Allaah is the Source of strength.