Possible meanings are 1) the shields appear red as the light from the sun reflects upon their metal surfaces or 2) the shields are covered with leather that has been dyed red.
This can be stated in active form. Alternate translation: "when the soldiers have made them ready" or "when the soldiers have prepared them to attack" (See: [[rc://en/ta/man/translate/figs-activepassive]])
This can be stated in active form. Alternate translation: "the soldiers wave their cypress spears in the air" (See: [[rc://en/ta/man/translate/figs-activepassive]])