It’s not very hard to qualify for Mercedes Fleet. If your employer is not a member, a number of clubs offer fleet as a benefit (United, PenFed, Morgan Stanley). We have a thread on this forum with tips on how to qualify
Edmunds is saying you should be getting $1000 dealer lease cash with no fleet incentive. If your are not being told about it, then assume they are baking it into the discount. Have them break it out instead.
The 2 MSDs will lower the payment around ~$10/mo. With the MSDs, the MF is effectively zero, and the Mercedes warranty is 48 month, so unless you like changing cars, stretching the term to 48 months does not significantly incur more rental charges. This will save another ~$25/mo.