Nope! The only check, as I recall, is when you choose a realm or finalize character creation (as it checks the name chosen against the name list of that server). Basic character creation is done client-side.
You do have to be able to get the initial connection to the server to be able to log in to a world and choose to create a new character, but if you can't do that, then, well, rip everything.
Personally, I'm still going to fantasia straight into a dragonprincess because another major component of the decision to stay Au Ra or not will be how the character looks in my massive glamour wardrobe; the benchmark is honestly pretty good at giving you an idea of how the character will appear in a variety of light situations, but how the character looks in all this junk I've accumulated over the content cycle looks good on the character. We will find out in 21 hours!
Meanwhile... on reflection, I can think of one reason for holding back the Au Ra conventions until exactly launch.
One. And it would be the most hilarious bait-and-switch I've seen all year. The evil little part of me dearly hopes my hunch is true.