The package wrapped in a white napkin is three matzo called "the Unity" that is used for part of the ceremony. As Christians we see this as a symbol of the Trinity.
There are many scripts that can be used for a Christian version of the Passover service. Over the years I've adapted one from Family Celebrations at Easter by Ann Hibbard.
Below is the platter of symbolic foods: roasted egg, lamb shank bone, charoseth, horseradish, parsley, and salt water.
Lighting the candles: "Blessed are you, O Lord our God, King of the universe. You have made us your own. We light these festival lights in your Name."
"Wine" (sparkling grape juice for us) is poured and sipped four times: the Cup of Sanctification, the Cup of the Plagues, the Cup of Redemption, and the Cup of Praise. If Passover was anything like this in Jesus' day, the cup he passed after eating (Luke 22:20) would have been the Cup of Redemption. Even if it wasn't scripted like this back then, it's still great fodder for reflection now.
We really are quite solemn! Partway through the ceremony, we pause for dinner and relax a bit. Dinner is roast lamb, potato or grains, green vegetable, charoseth (apple salad), and matzo.
After dinner the children hunt for a hidden matzo (much silliness by then). We then finish the ceremony ("Next year in the New Jerusalem!") and have dessert--a lamb cake, ice cream, and strawberries (strawberry sauce this year).
This tradition has been a blessing for our family over the years. It's almost Holy Thursday, but it's not too early to file away ideas and lists for next year if you'd like to join the fun.