Passengers who choose not to purchase ”Priority & 2 Cabin Bags” and arrive at the gate with 2 bags, your second larger bag (10kg weight Dimensions: 55cm x 40cm x 20cm) will be taken off you, tagged and placed in the aircraft hold free of charge. Please ensure all valuables are removed. You will collect this bag at the baggage belt at your destination airport.
Since this means I will not take my larger hand luggage on board, can I transport fluids in it, like in regular checked luggage?
No, the same rules apply as for "actual" hand luggage. Otherwise you could carry your >100ml liquids through security in the bag that will go in the hold, transfer them into your hand luggage after security, then take them on to the plane.
You can transport fluids in any hand luggage. There are only restrictions on liquids that you can bring through airport security checkpoint, and it makes no difference whether you plan to bring it onboard an aircraft or not. Any fluids that you obtain after you've passed the security check, are okay for bringing onboard, as long as they fit in your hand luggage allowance (which may or may not exempt counting purchases from duty free zone towards general limit).