Avada Kedavra and Explariarmus sounds would be cool same with the snapping sounds of standard spells
One of the boots have like"The boy who lived... Come to die... Avada Kedavra!" Would be so perfect
Sorry if I'm spelling those two wrong though. I'm also a big Harry Potter fan but I still need the books too x.x Sorry to get off topic but yeah. Maybe have two different hums, the hums from the Death Eaters flying around would be a good one and the Expecto Patronum spell hum would be good for a light side kind of hum then just because have Hagrid's bike hum for another him option
Lockup would be the two big spells in a lockup basically. The standard spell snap sounds would be for clashes. Not sure on swings and other sounds though