The Retinues are the armored ones. You might have thought they were billmen or something. They have higher attack (8) and as much base armor (no shield) as the pavise crossbows. Prediction: they will rip the crossbows apart.

The defense skill only applies in close combat, according to the descr_unit file. This may or may not be accurate, since I notice that light skirmishing missile troops (cossack muskets for example) with reduced or no armor upgrades have very high defense skill (9 in this case). They don't need to fight in close combat (especially Sherwoods who unlike normal longbows have no AP weapons), so why give them a defense skill that is so high? But yes, unit experience still affects the test because you can kill the enemy faster and cut down on return fire, increasing your advantage with every salvo.