Hashirama wins with the Budha and Flower Tree World.
This exactly Buddha, Flower Tree World and I would add Wood god gate.
Buddha doesn't have any Anti bijuu skills, but it has great AOE attack and the main where the main obstacle lays is it's destructive power
Flower tree world is incredible hard to deal with as it spread sleeping pollen around make Naruto speed advantage over him useless. Only Naruto hope would be TBB Flower Tree world before it spread sleeping pollen.
Wood God Gate is the most durable and hard to deal with attack of Hashirama for Naruto because once it fall down on you you are restricted and unable to move, but Hashirama would need luck to hit Naruto with Wood God Gate.
I also don't mention Wood dragon for reason. The reason is simple I doubt Naruto fall in that trick again, also one TBB and wood dragon is destroyed. Wood golem would be deal with quite simply also. Other wood releases attack are too slow or too weak to be important.
However Complete Kurama BSM Naruto would takes this mid diff.
IMO: (Fanfic)Complete Kurama BSM Naruto > SM Hashirama > BSM Naruto > Base Hashirama
BSM Naruto beats Base Hashirama low-mid diff
SM Hashirama beats BSM Naruto low-mid diff
Complete Kurama BSM Naruto could beat SM Hashirama low diff.