So I heard there’s an event where Keisuke and Daichi spy on Alice and Aida. Does any know what event that is? Also, what are the variables in the debug menu for?

I don't think we have a scene like it. Closest to your description is MC007 which is size 2 scene unlocking after any 15th event if player isn't on Akira or Alice's routes. The scene has Alice and Akira (not Aida) though and it isn't technically about spying on them per se