Good questions, it is common to have a leasing fee equal to 100% of the first month's rent. Some of this depends on property location and how many units you have with the PM. The leasing is a lot of work, advertising, showing the unit, running application and the credit/background reports, verifying the information, doing the lease signing, etc.
The first month's rent does encompass everything to place a tenant we don't break out separate marketing fees, it's an all inclusive fee, the first month's rent.
Negotiating is up to you and the PM, where the units are located, their condition and also what services are being offered. Does the PM mark up maintenance requests or pass them through at cost? Do they keep late fees or pass them onto you as the owner? Do they respond quickly and keep you well informed? If they place a tenant they have to evict do they place the next tenant at no cost to you? A lot of variables to consider.