In general, an elliptical distribution of lift along the span is close to the optimal with respect to maximizing L/D.
Correct. This minimises induced drag. It can be obtained by using an elliptical wing planform (e. g Spitfire) - but that is expensive to build. For a specific design point, such as a given angle of attack, it can also be achieved by a simpler wing shape, such as straight taper, combined with a wing section that changes along the span. Washout may also be incorporated to give friendly stall characteristics.