It will be activated - but it not guaranteed to happen before the date of service activation.
When you call support they will ask for the Broadband phone number and you will be able to get them to mark your work number as an alternative number along with a mobile and at te same time, making your new number teh primary for contact.
Not sure if my comment should be before or after the quote; sorry if I have it round the wrong way this time.
As for email activation just prior to or on the day, that seems to be the BT way of doing things. It is not like that with other ISPs whom I have dealt with the email service available very soon after placing the order. In this case it would have been very handy for early activitation.
As for giving a hotmail account as the contact address, hmm, never thought about that at the time.