I love your ideas, they would go nicely with my wedding game pack ideas.
Also an anniversary system is one I'd like, the sims use an equivalent amount of days to give paper, tin, gold anniversary based on the lifespan settings, anniversary status is stored in their relationship panel (like parenthood "best buds" or "happy childhood") and they could throw a anniversary round the time where gifts are themed to the material. (Paper = cards and money, ceramic = vases, plates, china sets, etc)