Can you play online coop with just 2 people or do you need all 5?
Sure, in a private lobby. I do it with my cousin all the time. If you mean a PUBLIC lobby; no i don’t think you can unless three people leave.
Just to add to @HandsomeCam point you also still gain lore challenges in private pve but not private pvp.
@pizzonage Is correct. I do THIS all the time as well.
No problem, nice to see a new player. Enjoy!
Yep good luck with your stories tip for it is try to avoid splitting up as it causes more spawn packs to start spawning. Not a huge deal in normal but hardcore and advanced it’s safer.