I think all of your questions have been answered correctly.Is this the case with Essentials classes their choices are locked down to just four possible options (using 10th level Utility as an example), so not only can they not use any previous 4th Ed Fighter utilities, they can't even use the Essentials Fighter Utilities of a different class? If so why did they call them Fighter Utilities and not Knight or Slayer Utilities?
Most of the information in the Essentials character classes is presented in a simpler form for its own sake.
I think the reason for the simpler presentation is to make players of other D&D more comfortable with the the character classes.
All the Utilities are shareable to all the fighter classes including Slayer and Knight.