It looks like everyone took a break this weekend

Celebrities will talk to you almost about everything.
For example it doesn't have to be Star Wars related. Ray Park and Warwick Davis would talk about up coming projects (GI Joe and Harry Potter).
There are celebs that are more vocal than others; very talkative celebs are: Ray Park, Ashley Eckstein, James Arnold Taylor, Dee Bradley Baker, Daniel Logan, Jeremy Bullock
Not very talkative from my past experiences: Tom Kane and Jake Lloyd (like I said before Jake just seemed "out of it")
Now the problem with celebs that are talkative is that they'll spend more time talking to each guest and then have no time at all to meet anyone with a standby pass.
For example: Matthew Wood (voice of General Griveous) talks alot and he only could see about 40 people per signing hour. Peter Mayhew (Chewbacca) didn't talk at all and could sign more that 75 people per hour sohe would be able to get people with guaranteed fp and people with standby's.