I'm sorry to say that the answers to all your questions (in order) are: 1 - doesn't matter, 2 - doesn't matter, 3 - doesn't matter, 4 - doesn't matter, 5 - doesn't matter, 6 - doesn't matter.

He's looking for a notebook (a tabbed widget/control/whatever, it's got tabs).

Calling it a "widget" hints it's probably Tk, but it doesn't matter :)(pretty much every toolkit has one)