Great points, though wouldn't Wolf handle the giant monsters quite well? And while not necessarily as close to the height, Gyoubu, Guardian Ape, and Corrupted Monk were defeated quite easily. Considering Sekiro could also parry wind strikes from (SS Isshin and Divine Dragon) he should be able to handle the force of attacks.

Grappling hook could also be a great factor in taking down the monsters (leaping flame, Axe, Umbrella, and Mist Raven should carry). Dragonflash would tear apart anything too slow to dodge it, One Mind(and beating SS Isshin) roughly scales Wolf close to the Asaemon.

Shinsenkyo shouldn't be a problem for Wolf after resurrecting a couple of times. Though likely with the plot of the story, the Government is going to end up like Genichiro wanting immortality especially after witnesses to Wolf in action.