Mnogaya Leta. Congratulations. May they blossom and grow and run in green fields and walk in enchanted forests and come out having defeated the witch and captured the treasure, as the happy tales go.
Moxie and Pepsi are good twin names, not to mention the fact that they hail from the underrated
Bored of the Rings.
Another good one is Eagle and Child. Or, if you want to go casual, Bird and Baby.
Seriously though, congrats, and good luck. My mum has an identical twin, they're loads of fun. And sometimes they're not so fun, but we won't get into that. Their names, if you're interested, are Tatiana and Natalia.
Cheers!