Jaheira - Insect plague (on Solars - possibly even Jonny if he is near)
Keldorn - Carsomyr - on Jonny as soon as his PFMW wears off (listen carefully)
or use his Dispel magic on Jonny
Kensai/Mage - time stop and hack + Balthazar is probably immune to time stop - he can help (don't tell him what to do - just point in the right direction)
Also spell Immunity-Abjuration (If Jonny wants to dispel, remove, breach you)
Minsc , Aerie - help
Potions of Invulnerability, Potions of Magic shielding, Potions od Magic Blocking, Potions of ...
Ignore Imoen !
Or maybe have her chase Aerie while you fight !