Do I have to have Tool cards in my discard pile in order to use Rotom V's "Scrap Short" attack? Or if I have Tool cards in my discard pile, do I have to choose at least one of them to put into the Lost Zone?
You can use Scrap Short if you don't have any Tool cards in your discard pile. Scrap Short does not require you to put any Tool cards into the Lost Zone; if you cannot or choose not to put any Tool cards into the Lost Zone it only does the base amount of damage.
Scrap Short