I have typically 1 graveyard per world. Most are in Parks, but one is on a Spa lot, and another is on a Bar lot. I like that a graveyard can be a corner of most any kind of lot. I never missed a specific graveyard lot trait, because I'd see it as wasting my lots - we already have way too few lots.
I have a few traditions when sims die. The family will normally keep the stone/urn at home for 1 year. It gives them plenty time to mourn. Within 1 year they have a funeral gathering, moving the grave to the graveyard and releasing the spirit. Yupp, in my game it's not allowed to keep a spirit, there are a few graves around and about though, of very old residents who were never released, so a couple lots are haunted. Besides, Windenburg is outside my Region 12, so most rules don't apply to them.
I never build a church or other monumental building on my graveyards. The ceremony only takes place next to the grave and is normally just a quick gathering for relatives. There will normally be a "floral wreath" decorating a new grave for about 1 year, then graves are mostly decorated with a living plant. I remove those plants for very old graves with no relatives around to tend.
In the future I might build underground chamber(s) for storing urns - if graveyards become full. Then there might also be a ceremony chapel room, sort of. That's not gonna happen very soon, though.
