Yes, microdosing during a cacao ceremony or taking part in a ceremony while you are in a period  of microdosing is possible. Cacao contains compounds such as theobromine, phenethylamine,  and anandamide that are known to have psychoactive effects.
One of the primary benefits of combining cacao with psilocybin is that it can help to mitigate  some of the negative side effects of psilocybin, such as nausea and anxiety. The theobromine in  cacao, for example, is a natural vasodilator that can help to relax blood vessels and promote  healthy blood flow, which can in turn help to reduce feelings of anxiety and discomfort.