Another option for graveyards is to build an above ground vault/mausoleum that leads to catacombs for urns to make use of underground space too. Another vault/mausoleum could lead to a vampire or skeleton residence.
Making a graveyard/wedding venue combination is another option. Build a vicarage or apartment for the resident as well as a church hall or other space for the reception (remember to set the front door of their home as the front door). Graves can go in the church yard or catacombs. Lot can be haunted or just regular residential. You can throw parties at another sim's house as long as you know them and invite them, so weddings are possible, as are funerals (with mods).