Since you know them well you have knowledge about allergies, likes and dislikes. Since its your home and your dinner, serve something easy on you.
Perhaps big pans of lasagna - some spinach, some spicy sausage, etc. then salads, again variety or fun make your own with bowls of lettuce, arugula, romaine, carrots, celery, on and on and on then dressings choice.
Plenty of crunchy breads and spreads.
For dessert the choices might include chocolate, or cheesecake, or strawberry shots, or heart cakes, cherry pie, anything in the theme.
If you want decorations go to Pinterest for great ideas of plantable hearts, fun questions to answer when popping red balloons, etc.
Please let us know who the event turned out!