I don't think a 30mm will cut it, width-wise. Last night, I processed photos from the character dinner at Garden Grill, and there's a great shot of Chip (or is it Dale? I can never tell

) and my son and wife, taken with my 28-75mm - and the edges of the faces are all cut off. Argh! Actually, I just checked the focal length and it wasn't zoomed out all the way, but other 28mm shots are just
barely wide enough, and I remember sliding my chair back to get everyone in (and forget it unless everyone was crammed together.)
I did often use my standalone flash unit, with the built-in diffuser flipped down. This usually gave good results without overpowering things too much. Actually, at Garden Grill, I was even able to bounce some off the low white roof - which is often not an option - you couldn't do it on the outside row of tables there, or at Crystal Palace, or Liberty Tree Tavern, or Chef Mickey's, etc...