If I were you I would get the Pixie. Pacman frogs look nice but they virtually never move except when grappling with a food item. Pixies are also a lot tougher when it comes to terrarium conditions. Keep just that frog for a couple of months. Then see how you feel about other things. There's a real pattern of new amphibian keepers trying to collect piles of species. It's hard to resist, believe me I know. But if I can pass on one piece of advice, as someone in the amphibian hobby for decades, it's that you go slowly, and keep it manageable. It will benefit the animals, and you'll get to see interesting behavior that you won't notice if you've got 20 kinds of frogs in your home.