Have you checked on the Edmunds forum what the current lease incentives are for the 3 series? Going by the MSRP it appears this is for a 330i? You can also check out the BMW lease incentives page for info about current incentives.
Although you may not qualify for loyalty or recent college grad incentive, I would suggest signing up for a Penfed membership for an additional lease incentive. Here is the link to that thread. You can also sign up for an upcoming BMW event to get an OL code (there is a ton of info here on how to obtain an OL code).
As for the discount you are getting, since all fees are rolled into the price, it will be best if you get a breakdown of the fees (acquisition fee, dealer doc fee, title and registration fee) so that you have a clear idea of the actual pre-incentive discount off MSRP (before any fees). Is the quote for a 2019 or 2020 car? Is it a brand new car or a loaner?
You mentioned the dealer does not want to disclose more info via email. It is a sign for you to shop elsewhere.
My $0.02.