If Barca wins the games against Lisbon and Kiev, then they will definitely be in the next round, since it is unlikely that Lisbon will win against Bayern. Only if Lisbon wins against Bayern and Barca loses against Bayern, then Barca would be eliminated (if Lisbon then gets at least four points against Barca and Kiev). The only question is whether the new interim coach can turn the tide so quickly or whether the problems are not deeper and need more time to fix them.
Well it is at least a home game for Barcelona, but don't forget that they still have to win against Kiev in an away game. That is not guaranteed in my eyes, by no means and even Kiev has a chance to at least make it to the European League. If they manage to beat Barcelona they can still make it to final CL round in the last game against Lisbon.