Defense skill never work for any other direction than front and right. If a unit doesn't have a shield value, then it simply doesn't get any shield bonus.

As for unit creation, you can find the unit name in the EDU. It should be the first name given. For example, for 1 basic Pahlavan horse archer with 2 experience, 3 armour upgrade and 4 weapon upgrade in Persepolis it is:

create_unit Persepolis "steppe missile cavalry pahlava shivatir" 1 2 3 4