Leaves, particularly fall leaves (autumn leaves), should be completely dry before using it as an organic material for making bokashi. Any moisture can harbor microbes that can interfere with the bokashi fermentation and result in something that smells like low tide. The leaves should therefore be dry enough to easily break up into small pieces when crumpled in one's hand. All of the leaves in your batch can then be much more easily turned into tiny pieces. This makes it easier to mix with the EM-molasses-water liquid.
While making bokashi leaves is doable, it may be preferable to just use the leaves (untreated/not fermented) as ground cover, when trenching/burying bokashi food waste, or when doing composting.