I don’t have any employees, but have a number of independent contractors who do work for me.
Personally, I give my access to no one. If you don’t want to gather creatives yourself, ask the programs if you can open a second account, let them go in there to pick up stuff, and then have them alter the tags to match your primary account. That way only you can see your stats or change your personal info etc. Personally, since I do sales etc. I want to pick the creatives myself and am not handing that off.
I pay different people differently – usually they start out being paid by the job, and as I learn to like the work, they move into more responsible positions and I eventually figure they will be working x hours a week and pay a steady sum. People like that better – something to count on.
I also like giving bonuses when we have great months, or if someone does an outstanding job or something.
Deciding what you want to contract out and what you want to do yourself depends a lot on what your strenghts are. Keep doing what you are best at, and contract out the rest.