2.8 isn't that shallow? He's probably going to be pushing closer to the long end, so closer to 55, and at least 10 feet away from someone. Doesn't that leave like 8 inches to work with? That's IF he's that close at 10 ft away. Since he's using crop he's probably a little further since that's pushing into the high 80s-ish...
Philc123 - The third photo is the best of the three. Though, as discussed, subject isolation would've made it even better. I say shoot in AV mode and just see what you can get away with, depth of field wise, around the house. Get used to seeing the difference between 2.8 and 8. Figure, if your subject(s) are on an even plane shoot closer to 2.8. If you have a bigger group and want to show more depth, shoot closer to 8. Shooting in AV will help you see the difference of what aperture does and let you hear what acceptable shutter speeds are before you even look at the viewing screen. From there, you can dial in those shutter speeds / aperture settings when you want to move on to manual. Lastly, I usually shoot in AV during an event anyways. For me, it just seems more in control than P and less likely to miss a shot in M.