Air carrier flight crew flying an A320 aircraft reported hydraulic system fail and a multitude of other system failures inflight. Flight crew landed uneventfully.

Narrative

Initially we [requested priority assistance] for the green system hydraulic indication dropping. Then various failures started like Autopilot One failure at about FL200. On final approach Cabin Pressure amber ECAM appeared with the outflow valve closing; descending through 4;000 or 3;000. Then through about 1;500 ft; the 'thrust levers not set' message continually kept flashing with the aural warning ringing every time. The Captain kept trying to set Support per the message but it would just spool the engines up without setting the automatic function. Even though he disconnected the auto-thrust the message would briefly appear and disappear any way all the way to touch down. After landing the emergency personnel verified the aircraft was clear of abnormalities and we taxied to the gate normally. The after landing flow was accomplished nearing the gate so the slats not fully retracting after shut could have been because both engines were already shut down; but the message appeared in amber.