Matthew,
best advice is probably to register asap to avoid the chance of being turned down if too late. They are well organised, but overnighting mooring facilities are of course limited.
As for general info, they'll send pretty comprehensive information by mail later. They will offer fair accommodation Formule on the camping ground in Port Blanc in separate 2- and 4-bunk cabins including breakfast, or you'll have to look for accommodation yourself. Slim chances by now.
Cross-Channel ferry bookings are your own business. During the event, they have a fleet of free buses to ferry crews between locations. Likewise, a fleet of ribs and dinghies ferry crews out to their moorings. Great friendliness all round.
Safety equipment: Foreigners have leave to limit their own safety equipment aboard their boats to what is standard in their home country. No sweat, all very friendly.
One thing you better bring is a navigation chart of the area. There is a big 'Comptoir de la Mer' chandlery in Auray, but it is not easy to find there.
P.S.
Proper navchart is SHOM 7137L .