As for Sarah-Wuff's howling, she
did howl the fiirst time she shifted, way back in the "Spielberg" section. I think the franchise reqiures it...
And being up close in the classroom; were she to shift and howl, I suspect there wouldn't be an intact eardrum left among our merry group of Metamorphs...and we don't know that they all heal as fast as the Werewolf-types. It may be possible that for some, damage is permanent and not subject to "instant healing".
And Jean's "intervention" would be on
her own behalf and nobody else's; as per the Wiki.
KMacK...
"You don't have to be invisible when everybody is looking the wrong way..."
Writing the series "Wulfen Blood"... getting ready for publication.