What happened to the other Great Weapons Li'l Seb was carrying? (The Needles of Zillywair and what not.) I know they were created by the Tricksters, but what happened to the specific three that were being carried with the Warhammer by the bunny?

You mean Liv Tyler (different bunny) the one given to John that had the warhammer of zillyhoo.  The other three weapons it had weren’t trickster weapons