Not true. JK has stressed that not even her husband knew about the plots. In fact she said she chose to keep Arthur alive in order to keep Ron immature and happy-go-lucky and serve as humour relief for the Trio.
The easiest place to draw inspiration for a Halloween costumes this year is right in front of you — your TV and computer screens. Take a cue from pop culture and dress up like your favorite characters (Cheap Diy Costume)