Here's my idea to why his trump card should have nothing to do with hashi. Hashi couldn't of been part of the plan seeing as how up in till orchimaru resummoned him he was locked away inside the dead demon seal. There's no way madara could of accounted for hashi being there at this time, so his plan if it was predetermined shouldnt have anything to do with hashi.
I think hashi's sage mode is original! The wood technique probably uses natural energy as well! The reason I say this is because I believe this is what madara wants to take from hashi!