Sneaking would allow you to tail them from a distance, and perhaps sneak up to someone to land a blow, (and then you are detected). You cannot wait in a pipe and be unnoticed. Think covering yourself with sludge and standing close to the wall, playing dead and so forth.
But I honestly see no tactical need for all of you to be in the same place, I think it just hinder you. (I am not such a great tactician though). I think it is perfectly fine that one of you is actually in the drop point and record the transaction and the others are not long behind in case your smugglers decide to escape. Staying out of sight in a distance, after a junction and then carefully tailing the smugglers as they pass you is something you can do with sneaking. Waiting for them in ambush stationary disguised as part of the environment is disguise.
If you are okay with that interpertation I'll assume that Kynos is at the drop sight hidden behind some trash, and Ayato and Irris of you are going to close in on them as they approach the sight? Please clearify so I can continue and resolve the scene.