Starting at the end, this is a horrible offer for a leftover 2018. You should aim to get up to 20% off before incentives. It is probably cheaper to buy a Model 3 than lease an i3 at that monthly price point. Ouch.
The lease credit is the same as the federal credit. BMW owns the car during the lease but they pass along the federal credit to you.
That is correct - the 7500 Fed Credit goes back to BMWFS that’s why you are getting this rebate.
The money factor is also inflated from the base of .00177 while your discount before incentives is laughable and I would encourage you to find another dealer or focus on the 2019 which has better range and some new features like adaptive led front lighting. You should shoot for anywhere from 13 to 15% on a 2018 model and I my opinion push for at least 10% for a 2019.