Member-owned theater company Synthetic Unlimited will host a Day of the Dead Dance Party and Theatrical Showcase fundraiser Friday at the North Columbia Schoolhouse Cultural Center. The company, which promotes itself as Northern California’s only member-owned alternative theater group, has staged productions for the past three summers with impassioned modern interpretations of classic plays, including the recent “Antony and Cleopatra.” Synthetic Unlimited is expanding next season to include two full stage productions, a full black box production, six staged readings — and a few other one-nighters that they promise will be a great time for everyone and offer opportunity for …