Well-executed re-write. I'd say a clear improvement on the original.
But the Foundation encountering straight-up folklore has been done; and I don't see anything particularly unique or compelling about this visit to the trope.
And I find his friendly, cooperative attitude towards the Foundation completely at odds with the sort of personality that would prank a killer oni just for the lulz.
That's aside from the fact that such a crippling injury should leave an (ahem) impact.
Maybe he could still be attempting pranks on Foundation staff, but keeps running into his physical limits. Mounting frustration leads to a continuing pseudo-cheerful demeanor, but increasingly mean and dangerous prank attempts. Perhaps showing him gradually learning to cope with his disability and/or recovering faster than physical therapists were led to believe. Near the end, there could be breaches and staff deaths that they can't prove 746 is responsible for, but next day he's in the first legit good mood they've seen in a while.
As is, -1 for not hooking me.