I hadn’t thought of that, but it’s not him
And technically, I could argue that Vasher is not the same as the person who died.
Edit: I have to go bed sometime in the next hour or so. So I’m going to give yall my 6th hint now
1 This character is dead
2 This character was cosmere aware
3 This character was on Roshar at some point
4 Wit knows this person
5 betrayed a friend
6 was killed by the friend they betrayed(this might make it really obvious)