Incapacitating enemies is a thing you know.I suppose I can look forward to being intensely amused if it turns out the Witches had back-up and upgrades from canon and we could have set off a giant clusterfuck by sending in the Jojos and making them panic.
Honestly all the fear mongering is just going to make things worse; Joseph and Jotaro are skilled enough to not kill them even if the witches are going all out.
Stop underestimating their capabilities and let them aid in this.