Scenario1: Against base Hashirama, i'd say they would handily. The most dangerous move for me is the flower tree world, but with Tobirama being there, the team would have full knowledge on his brothers moves. If Hashirama at some point in battle used FTW, Minato may decide to summon Gamabunta, who is comparable in size with a Bijuu like Shukaku [
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], so just like with Madara's Susanoo [
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], Gamabunta would crush them with his footing alone [
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] and if they stay above Gamabunta, they also are situated in a area not affected by the pollen(since the Kages and Madara weren't affected in a similar height). With Gamabunta's fire power, Tobirama's suiton suidanha(or GK if we count edos), they have sufficient means to destroy the flowers responsible for the pollen
As for the Mokujin, it seems comparable in size with Gamabunta(most likely greater but not by much imo). Minato was capable to take advantage of his speed to directly summon Gamabunta on top of the Kyubi and pin him down [
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], and i consider the mokujin to be physically weaker than the Kyubi. With the use of Hiraishin, it gives openings for Minato to proceed this way and at the very least neutralize the Mokujin with a boss summon, the time others handle Hashirama
On the other side Hashirama would always have to worry about combo attacks with Hiraishin, Gated Move speed and so on
Scenario2: Practically the same as scenario1 except with Shinsuusenju. Would depend if Hashirama can still reform Shinsuusenju at will or not(in case a Hiraishin user made it disappear. If he can, he wins, if not anything can happen but i tend to give Hashirama the win ultimately
Minato isn't warping Shinsusenju away without premade seals somewhere else on the battlefield. Nor does an alive base Minato have the chakra reserves to do so.
Jubi's Bijuudama was far bigger than Jubi's itself. At this point, it was already bigger than Jubi [
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](bottom panel). Shikamaru says a page later, it's getting bigger and bigger [
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] and bottom middle panel we even see how just 1/4 of the Bijuudama at that moment made Jubi look like a dwarf and it was continuing to grow and grow all the time after that(when alliance was panicing and starting to think about strategies and so on), so it's safe to assume the Bijudama in question was far bigger than Shinsuusenju as well, yet Minato warped it in base with minimal effort(we didn't evn see him a little bit exhausted after that)