In a medium bowl, toss the mango and strawberries with the lime juice, sugar and lime zest. Let sit, tossing occasionally, until the fruit is very juicy, 30 minutes to 1 hour.
When the fruit is ready, slice the pound cake into 12 equal pieces. Heat 2 tablespoons of the butter in a large nonstick skillet over medium-low heat. Sprinkle half the coconut in 6 small piles in the skillet and place a slice of pound cake over each pile of coconut. Cook, pressing down with a spatula, until the coconut is toasted and the pound cake is warmed, about 3 minutes. Flip and toast on the second side of the pound cake slices until warmed, about 1 minute more. Transfer each slice to a plate, scrape out any leftover coconut in the skillet so it does not burn and repeat with the remaining butter, coconut and pound cake slices.
To assemble, evenly divide the fruit with the accumulated juices among 6 slices of toasted pound cake. Top with a large scoop of ice cream, about 1/2 cup each, and a second slice of pound cake.