All right, I've (perhaps unfairly) gotten the easy stuff out of the way, but the last comment is somewhat colloquial and I'm having trouble fitting it into the context. At present I have it as "What's the matter?" acting under the assumption that it's actually Fate and Nanoha talking to one another. Feel free to correct me on this. As usual, removing request for translation. I may move onto the next one now or in a few days (when the mood takes me).
Santa?Ah, Vivio, you don't know who Santa is?Don't know~The one they call SantaEvery year, at Christmas time, Santa comes to visit all the good kids and give them presents.Yes♪
A very good girlWhat's the matter?Is Vivio a good girl?