"Shei Vinitras shouts, {S}" - Corruption cure the player listed. Will get achievement "Don't cut the strings" plus the player won't die.
Alien looking mobs spawn near other players, so it is best to have players standing on the platform so that the mezzer can see. I know other groups have punted them off the platforms to succeed as well. As for mezz spells, even TOV era mezz spells work on the alien adds. Beam of Slumber, Noctambulate, regular mezz spells, AE mez spells, they all work. For the healing adds, they can be killed, but most groups just ignore them and outdps the healing that they provide.