The Grand Californian opened without fanfare. It wasn't until a month later they held their official grand opening (on February 8, 2001) to coincide with the opening of California Adventure park.
They've had small parties at some openings. Not sure if Villas at
Disneyland Hotel will be similar, or since it's California - they'll do less or more?
For example, here is a video of Copper Creek
DVC opening: