Is raising the hands for supplication in unison after the obligatory prayer, and raising the hands for supplication while sitting in homes, and raising the hands before or after bowing in congregational prayer, considered Sunnah or bidعة (innovation)?

What these people do by supplicating collectively after the prayer has been previously explained in Fatwa no. 62068.

As for wiping the face with the hands after supplication, scholars have differed regarding it, some deeming it recommended and others disliked, due to the weakness of the narrations concerning it. Therefore, no one should be rebuked for doing it.

Raising the hands during supplication is recommended according to the most preponderant scholarly opinions. The general rule is that supplication is permissible whether in a gathering or elsewhere, but it is not legislated in worship to adhere to a specific manner that is not mentioned in the Shariah.

Raising the hands when rising from bowing (ruku') is established in the sound Sunnah, and one should not abandon the Sunnah unless doing so leads to a disagreement that results in a preponderant harm.