Q. A manager is interested in repping me. I have two main concerns: that she would be due her fee in the event of a sale one full year after our contract expires, and that she wants to option to attach an Executive Producer to be named later.
Meaning herself. Managers do that.
She should only be due her fee after termination if the sale results from a submission she made. In other words if she sends out script A to company X and you sell it to company X six months after termination, she gets her fee. If you sell script B to company X or sell script A to company Y, she doesn't get anything. Often it takes a while for a signed contract to come through even after the sale is essentially made. A year is grabby, I feel, but that does seem to be the standard.
There should also be language that if you've gone 4 months without a "bona fide offer," you can cancel the representation.
Q. Should she sell a script of mine, would she negotiate on my behalf, or would I have to pay an agent an additional 20%?
You'd have to have an agent or lawyer negotiate the sale for you. Managers cannot legally negotiate for you, though in practice they essentially do. Agents get 10%. A lawyer gets 5% unless you can get him to work per hour.