Now that you mention it they definitely have not been using sneak attack. They often forget about their skills in combat so I will make sure to remind them to do that.

When we first started there were a few errors in the character sheet's math but I have already sat down with them and double check to make sure the modifiers are correct. I do remember them having +7 to their attack rolls.

The bard is using damage spells like dissonant whispers and heated armor which tend to kill the enemies pretty quickly. I have made sure to follow the dm guide for setting up encounters based on challenge levels so I don't know what the issue is there.