I would like a board calendar that shows on the front dashboard, and allows dates to be highlighted, ideally in coded colors (meetings, events). When a Board member clicks on the date, it should take him to the meeting page, or a document about the event.

Calendar with ability for board members to show their availability/block when not available.

I would echo this as there is no way to create an ad hoc meeting, you have to create a ad hoc committee first, then schedule a meeting.