Where is display name in My Space? Also can I have the default page as the forum rather than the Portal page?

I think there is an option to display or not display
portal page.

Have a look around portal settings.

I think the Display Name should be made as a BUG?

Do you have 'Allow Display Name Changes?' in your 'Feature Settings' - 'General' tab set to yes? Display name shows up in my edit profile with no problems.

You can turn the portal page off in 'Portal Settings' to make the forums the main page, but you obviously lose the portal that way.