Personally, I think is pretty useless to try to get posed shots as a guest shooter. At best, as Robert pointed out, everybody is looking at the pro's camera. At worst, my presence draws some of the eyes; so everybody (including the pro) gets a shot where half the people are looking in a different direction from the other half. Note the groomsman on the right in #3 and left in #4. He seemed to have trouble coordinating his eyes with everybody else's. As a guest, I'm more interested in getting second shooter type stuff. That way, I don't make enemies of the pro. So I would be looking for a shot like the one that Robert didn't like of the flower girls in an unguarded moment.
As for the umbrella shot, am I the only one who thinks this kind of posed artificiality is anything but the essence of lame? If I were the groom, the umbrella would be up a certain part of the photographer's anatomy if he asked me to pose for this shot. Or the photographer and his gear would be in the lake.