I think so if there were enough sacrifices from twelve of each species whether witches, werewolves, vampires or humans.

Um maybe the human massacre but im assuming the magic of hybrid and witch massacres were wiped away from travellers anti magic spell

I think that if a massacre of hybrids, witches and vampires were possible, the witch who assumed the expression would have an absurd power.

Yes they are hotspots that mark the earth for all time. Given the cemetery wasn't affected as a hotspot by the travelers spell I don't think any of the other places were affected.