For the chocolate cups: Add the milk chocolate chips to a heatproof bowl. Add the white chocolate chips to a second heatproof bowl. Divide the coconut oil between the two bowls and microwave separately in 30-second increments, stirring after each, until completely smooth, about 1 minute total. Set aside and let cool for 5 minutes.
Using a pastry brush, paint the entire inside of three cupcake liners with the melted white chocolate; don't be shy—really slather it on. Transfer to a plate. Do the same with the melted milk chocolate and three more cupcake liners. Place on the plate, next to the white chocolate cups, and transfer to the refrigerator to chill for 10 minutes. Remove the cups and repeat for a second layer. Return the plate to the refrigerator until the chocolate is completely set, at least 30 minutes.
Remove the cups from the refrigerator and carefully peel the cupcake liners away from the chocolate. Use immediately or return to the fridge until ready to use.
For the strawberry shortcake sundaes: Scoop 3 tablespoon-size scoops strawberry ice cream into each white chocolate cup. Top each with the shortcake, strawberry sauce, whipped cream and red sprinkles.
For the toffee coffee sundaes: Scoop 3 tablespoon-size scoops coffee ice cream into each milk chocolate cup. Top each with the toffee bits, pecans, caramel sauce, whipped cream and chocolate sprinkles.