A319 First Officer reported during descent they got multiple ECAM messages related to autoflight systems and air conditioning packs. After descending to a lower altitude the flight continued to destination for a safe landing.

Narrative

While enroute to ZZZ I was PF and we had just been given a heading off of the ZZZZZ arrival and a crossing restriction of 40 NM north of ZZZ at 12;000' and 250 KIAS by ZZZ center. I had put in a 40 nm ring around ZZZ in the fix info page and adjusted my descent rate to meet the restriction. While doing that we received multiple ECAM messages in very quick succession: ENG 1 EIU FAULT; AUTO FLT A/THR OFF; ENG THRUST LOCKED and AIR PACK 1+2 FAULT (Pack 2 was already on MEL). Receiving the AIR PACK 1+2 FAULT drove the decision to initiate an emergency descent to 10;000' MSL. The captain then divided the cockpit duties and had me continue flying and working the radios while he performed the 2 in and 2 out and requested priority handling with ZZZ center who then took responsibility for the weather avoidance. Once the captain began the ECAM Actions we started with the AUTO FLT A/THR OFF which had me disconnect the A/THR (Autothrust) and bring the thrust levers to idle. We increased the airspeed to VNE (Never Exceed Speed) -10 and deployed full flight spoilers to assist with the emergency descent. Once the emergency descent was completed; as well as the descent and approach checklists; we conducted a briefing for the visual approach to [Runway] XXR that included a review of the status page and noted that Reverser 1 was not available and verified that we were able to safely land on XXR with only the number 2 reverser operating. After landing I observed another ECAM message that commanded a manual opening of the Outflow Valve. This was accomplished while coordinating a gate change and managing 2 radio frequencies. Once we arrived at the gate the captain had us pause the checklist to ensure that our flight attendants and passengers were okay as well as to give them an opportunity to talk to us about any issues or concerns that they had. Thankfully our passengers and flight attendants indicated that they were all okay. Once everyone was off the aircraft we went back into the flight deck and continued/ completed the checklist; and got the aircraft handed off to maintenance.Lessons Learned: Post flight the captain and I talked and he asked me to debrief him and I noted that I had felt a bit rushed once we leveled off at 10;000 MSL and had considered asking for a short delay vector to give us more time but that ended up being unnecessary. I very much appreciated the captain and his leadership. I would not have changed a single thing about how he handled the situation. The new QRH procedures proved to be very effective and made the situation much easier to manage and prioritize. This situation made me appreciate the training that we receive all the more.