To the whole Dimitri holding the stake infused with magic thing-
I've read a fanfiction- yes i know its a fan fiction and nothing to do with the books- but it got me thinking about the wards and stakes infused with magic. Maybe, just maybe, Dimitri being able to hold rose's stake isn't a stroigi thing- but its a Dimitri thing.
Maybe only Dimitri could hold Rose's stake infused with magic- because well he's Dimitri. Maybe he does possess a little of his old spirit which makes him able to have contact with magic-not long or fully- but shortly.