I like your second image, with the background going toward a sepia tone and the group still in color. That's cool.
I also like OlBaldy's direction... headed toward some painting effect maybe. You could even do the background that way and less on the group.
Yes, while bracketing seems nice, if the images are going to move on you it is not as useful. You're better off taking few shots prior to the start, quickly upload to a laptop and judge the exposure. Then adjust as needed. Otherwise, grab a camera that can shoot in RAW so you can adjust all that later. (You can still do much of the same if
PS with JPG's, but depending on what the band expects and if you are getting paid or not... you may want to think about the RAW.)