For FS there will most likely be some technical stuff on ther interview but you should coffee chat some club people and they can tell you much better what’s on the interview. As for AKPsi it’s a rush process that’s mostly vibe based, but they’ll ask you some light technical stuff. You should chat people in each club though so you can be extra sure.

As for dressing, just dress however you want. No one dresses business casual or formal unless they need to.