How can I look at the tutorials again?

Either double tap a screen or go to the sidebar and select Help. This will start the tutorials again on each page.

Call forwarding seems to take a long time for the caller to reach me. Is there any way to speed this up?

The best way is to actually sign out of the application or just close it if you know that you would prefer to answer your calls from one of your forwarded numbers.

When I hit accept on a forwarded call, why is there a momentary delay before I can hear the caller?

There will be a momentary delay after you choose to accept the call as the system needs to determine that you are opting to take the call and then connect you and the caller together.