So, Noxias is not going to move, and he will still try to move north. However, if the consensus of the rest of the party is to regroup in the southern room then Noxias will change his mind and double move south again.

Polon will still make Dire Radiance ready for the first bad guy to be in range.

Yes, Noxias will fight from the catwalk if Konstansz does not make a move unless Rogur/Zeph encourage everyone to move one way or the other.