The underground competition works a lot like any kind of singing/performance competition would work! So as long as she's got a set, she's perfectly golden to participate, possibly for prizes!

There are some sparring rings where robots and other combat-related machinery go to spar and test out new upgrades. If he is an idiot enough to try and enter in one of those, he would be welcome, though every participant would be a bit worried about him. :( Because he would be sorrily outmatched.