K     E     Y          P     A     N     E     L     S     :

I think these are points of concentration knitting the whole work together:

(I've reduced the images in size to be legible on high screen resolutions. Might be better to write down the references and look them up in the phonebooks).

Church & State:
Volume II, page 966, panel 5:
Echoes.

Minds:
Page 136, panel 1:
Fate.

Page 198, panel 4:
Duality.

Page 251, panel 3:
Consequence.