How can capacitors pass AC without or with minimal voltage passing?
Within capacitors do not flow electrons. The dielectric material is indeed an excellent insulator.
In order to have current in a capacitor you need a time varying electric fields applied.
If the electric field is constant, than you got no current.
The time varying electric field attracts and push away electrons from the wires soldered to the capacitor.
The electric field displaces back and forth the fixed charges of the dielectric material.
Time          External E. Field         Displaced Charge          Current
--------------------------------------------------------------------------------
t = 0                                                                0
t = 1                &lt;-                  -   +                      15
t = 2               &lt;--                 --   ++                     10
t = 3              &lt;---                ---   +++                     0 
t = 4               &lt;--                 --   ++                     -5
t = 5                &lt;-                  -   +                     -10
t = 6                                                              -15
t = 7                  -&gt;                +   -                     -10
t = 8                  --&gt;              ++   --                     -5
t = 9                  ---&gt;            +++   ---                     0