[Opinions] To answer your questions...
1. They're fancy names, so I guess they would go okay together. And don't worry about countries of origin for your names; some people don't seem to care about where a name came from, only on how it would work on their kid, or how much they like it.
2. No, not to me. My name is Meghan, and I have a cousin named Margaret, which Meghan is derived from. As long as the names aren't the same, you'll be fine.