^Yeah, well James death had more of a purpose (plot whise). The others were more symbolic. There was no reason for Sirius to die, he didn't sacrifice himself or anything, it was only to take Harrys godfather away (curse you JKR). And Lupin was to showcase the brutality of war. He could've lived and nothing would've changed
^Exactly. If James didnt die we would have Harry Potter. Sirius was killed to hurt harry and remus couldve lived or died, it wouldnt have changed the story