i think the wand thing worked like this:

it was dumbledore's wand, until draco won it off him in the tower at the end of book 6, so it became his (even though snape killed him, it was draco that got the wand off him). harry defeated draco, so then it was his (even though draco never had that wand).

or something.

i'm really not sure about that whole "19 years later" bit. it felt like really bad fan fiction.