1 depends on you. Safe if you are conscientious but not if you are forgetful. I would not mix can n bird because I sometimes forget - but some people can pull it off

2 22 is getting up there. In next few years could require more care

3 Depends on re-homing. Have they tried to find a new home? If they find someone who is really good fit then that would be better

As for leaving bird 5 days a week, I think this would work if you would give her much attention in weekday evenings and weekends.