Probably only Hashirama will manage to clear all situations...
Situation 1:
Tobirama loses high diff. might pull off a win if his Edos are good...
Hiruzen loses, only thing he can do is RDS either Kurama or Madara, Madara being most unlikely...
Minato might cancel Kurama factor by FTGing it into the ocean, defeating Madara alone then still is a huge task, Minato 40-60...
Tsunade loses, if Madara is serious he can make sure Tsunade doesn't survive or he could just walk over her messed up body and destroy Leaf...
Situation 2:
Hashirama confronts and defeats the 20 shinobi, not too difficult situation for him...
Hiruzen is defeated and unfortunately so the kids...
Minato either sends a clone to confront the 20 and play hide and seek tactics or just FTG everyone out of the danger zone, I can see Minato clearing the situation...
Tsunade... maybe she survive but her team is dead for sure...
Situation 3:
Hashirama cancels the barrier, restrict the Edos and destroy Orochimaru...
Tobirama cancels the ET or just put his own 'talisman' in them and defeat Orochimaru...
Minato stalemates, unlike 3rd, RDS everyone with him and die...
Tsunade, unfortunately doesn't have answer to this either...
Situation 4:
Hashirama put Kurama to sleep and goes one on one with Tobi, let the NB decide who wins here...
Tobirama might win it completely or die like Minato. I'm not sure about this...
Hiruzen is defeated, he can't face both Tobi and Kurama neither 2v1 nor 1v1...
Tsunade, just like the old 3rd...
Situation 5:
I don't think Pain is good at being airborne...
Hashirama doesn't let him leave the rooftop and eventually take him down...
Tobirama,.. Hiraishin Giri???
Hiruzen might give a good fight, I'm not sure here 3rd 1v1 against Tendo path...?
Minato, most likely like Tobirama either finish the battle on the roof or FTG Tendo with himself elsewhere...