More Xbox Questions

Trying things out, nice so far.

My questions relate to using the Xbox One only.

1. Why do I have to sign in every time I start the app?

2. How do other family members login? Same user/pass or do they need account?

3. Why no 5.1 audio?

4. What's the word on that dvr beta? Looking good?

5. Interface hangs often when jumping through listings. I guess that's not a question.

Thanks for any info.