Airbus 343. Pax O2 is chemical and you don't have indications. Crew O2 low is a caution msg (amber) and OM says under abnormal procedures, that you may or not have O2.
. I would rather prefer something like "If you can read this, then you are not dead. That is a good start"
Then, no diversion. Anyway, accidents are always spying me, to change my sweet life. So take two O2 portable bottles into cockpit and connect both quick donning masks to them, they use the same fast connector
. In case you don't have the same connector, then you have a problem cause the first aid masks, mix the O2 with fresh air and if instead air you are into smoke atmosphere you are going to be a passive smoker. Another option are the smoke hoods that gives you 15 minutes but no communication with the other pilot or ATC. (very noisy the O2 generator).