Sorry to hear about the rejection. In terms of your question:
Q: Is the ban period still effective for other roles within McKinsey, including the Business Analyst role or is it only applicable to the (Junior) Associate role?
Not sure if they specified something in the rejection email. However when you fail the test, at McKinsey they ask to wait 12-18 months for a full-time position.
Sometimes when you fail a final round but you are close to a pass, they could mention a shorter period for the ban.
Given that in your case you want to apply for a different office and a lower position, I would recommend the following (unless they mentioned something else in the email):
- Wait for a minimum of 6 months
- Find a referral – you can find some tips for that here
- Disclose the previous rejection and ask if it is ok to apply at that stage
The person referring you will probably check with HR first. If they say yes, then you can apply again. If they say no, you can wait the period they recommend, without the issue of having another formal rejection as you would have not formally applied again via the website.