are these needed?

Lord Darcy created a lot of fixes for TS2 until the games were patched. No, most of these are not needed. K&B was patched up shortly after release back then. It wasn't created by the team at Emeryville or Redwood, but a different team no on site, and left out many of the bhavs it should have gotten like would include all the other packs' options. It was patched about a month later. However, on MoreAwesome Than You, where most of Lord Darcy's stuff was also listed, you may want the one that allows Sims (or place objects) to walk under modular stairs etc. Some of those are extra benefits, like that particular mod that Maxis never did add to the game. Those type of things are enhancement mods.

But no you don't need any of them, I don't have any of these installed once the packs were patched. Unless there is some extra enhancement mod I would want.