Combine the simple syrup, lemon and lime juice in a cocktail shaker filled with ice. Shake well, then pour into a medium saucepan and sprinkle with gelatin.
Allow the gelatin to soak for two minutes, then heat over very low heat, stirring constantly, until the gelatin is fully dissolved (about 5 minutes – it will still be a little cloudy, but no longer gritty). Remove from heat and stir in the gin or vodka and optional orange blossom water (adds a great floral note if you can get it, but it can be hard to find – I order mine online).
Whisking rapidly, slowly pour in the heavy cream to prevent curdling. Let set for about 10 minutes, until the jello reaches a pudding-like consistency.
Spray a small amount of Wilton Color Mist in one or two spots near the bottom a push pop mold, then spoon in the jello over top. Swirl with a chopstick, stirring stick, or the back of a spoon to create a marbleized effect and remove any air bubbles.
Repeat for each push pop, stirring the jello mixture occasionally to keep it from getting too solid to work with (it will be lumpy at times, which is fine). Cover push pops with lids, then store them on the included display box in the fridge until completely set, about two hours.