Can someone share with me some typical signs/symptoms of aging in our senior goldens?
Being unable to regulate their body temperature is one. Some may need a coat for the winter or blasting the A/C in the house in the summer. Arthritis is another. Also dementia which may be initially confused with loss of sight or hearing.
Out of the five things you posted I think #2 bothers me the most. A Golden not getting up to greet people seems strange to me. You might try Mirtazapine which helps with eating and attitude. I lost my first girl at approximately 10 and my boy at 13yrs 3 months. Both of them were chow hounds and people greeters right until the end.
Cherish every day and try to stay positive for your boy.