How to stay motivated and optimistic about an academic or industrial career with an extended PhD?
I'll say something only about your first concern. 

You can't change the past. You are where you are. However, I wouldn't be overly concerned with anecdotal remarks about what is expected or not. You have a history and if asked about it, just recount it honestly. Don't apologize for taking a few extra months or even years. 

The funny thing about (real) research is that you can't do it on a schedule. The insights and the background work take time to mature. It isn't like manufacturing a complex artifact like an automobile that can be optimized to the second. Research problems worth the effort are hard and the solutions come when they come. Sometimes spending more hours on them helps. Sometimes taking a break, especially a mental break, helps. 

But anyone who says "I will do this significant piece of work and be done in three years" is deluding themselves. I expect other people with research experience to recognize and respect that. If they don't, I expect that they haven't really worked on anything difficult lately and carried it to completion. 

You do what you can do with the constraints that you have. Hopefully you learn something valuable and are able to write it up and get your degree. But the path is both winding and difficult. 

When I went to grad school it was still possible to get a math PhD in four years out of undergraduate. I took seven. My career wasn't what I expected, due to economic factors beyond my control, but I had a rewarding career in academia. Nowadays seven is closer to the norm, unfortunately.