When sending payment THROUGH Zeus LSP, the LSP knows details where is the payment end point, when the payment occurs, & how much sats is in that tx.
No, pathfinding is done on the embedded node on the phone and therefore OLYMPUS (=Zeus LSP) does not know any payment details like destination and amount. Like any other hop, it can only see that something is sent. ACINQ (Phoenix wallet) is different because they do pathfinding for you. ACINQ node serves as a "trampoline node", meaning it is not a normal protocol-conform hop, but more like a relay for your payment. They know your payment details like destination and amount.
If your tx only has 2 hops, then Zeus LSP knows who is the sender.
OLYMPUS cannot know if there are more hops. So even if the payment is like this: Sender -> OLYMPUS -> You Then OLYMPUS has no chance to find out if "Sender" is actually the sender or just another hop.