I was asked at the last minute to take photos of a friends wedding, in the local courtroom. I think it was me or an IPhone. I agreed to do it, but I am not nor do I want to be a wedding photographer!
I stopped by the day before to see what I was in for. 30 foot ceilings and a dimly lighted courtroom. I asked the judges secretary to help me out and took a few bouncing off the ceiling. No good. Directly at her worked, but was harsh. Angled forward 60 degrees was about the best solution I could come up with, but she had shadows under her eyes.
I read a little the next day and decided to add a 4 by 4 flash card and leave the angle at 60 degrees. The result was better but maybe someone has a suggestion about what other things I could have done.
Tough situation. The second photo looks like you might be able to use those walls. Try to have the wall behind you and shoot flash backwards in 60 degrees or so. Maybe that could give you a better light? You can adjust the size of the light by adjusting your distance from the wall (this also takes away some power).
I think 1st and 2nd shots are much better than the last one. In my opinion, the facial expressions in the last shot look a bit forced but I'm not sure about this. You can decide You should not ask people to smile but instead do something that would make them smile. Jokes are nice and one thing I use quite often is that I ask people to show me their pirate expressions. First they are really surprised, then they do their expressions and after that they usually give pretty good smiles. Take the pirate face shot but be prepared to shoot right after they are done with that to get the proper smiles