THANKS everyone.... the frosting I ended up using -
Thanks to my sis who does this more often that I do, gave me her buttercream version which tastes wonderful. It is basically half butter, half cream cheese, vanilla, and powdered sugar to the consistency you want. I did:
1/2 cup butter
1/2 cup cream cheese
1 tsp. vanilla
4 cups confectioners sugar
1/2 tsp. Wilton white-white
The intertwining hearts were copied from the bride's invitations. To get the hearts glossy, I did a lot of experimenting with recipes and proportions and came up with:
2 parts buttercream recipe above, to 1-1/2 parts marshmallow creme (in the jar). It gave it a nice shiny look, and just soft enough to "round out" the piping.