Felt that 4 ages would be needed. Perhaps, a "Changeling Age" would be necessary, but given that we have 26 years between the Change and the Montival era, well!
Age I sees your community trying to survive, with "survivalists" being the backbone of your forces. These people are divided into melee units and ranged infantry. You also get survivalist cavalry too. You however get a professional military unit, a pikeman.
Age II allows you to upgrade these units into "farmers" - other units, including light cavalry, also follow suit. The other ages are self-explanatory, with more and more units become available.
Also realised that a variety of units - well, rather interesting ones - will need to be made available too! I read that balloons and gliders also seem to be possible units. However, NOT everyone might have access to them - I figured that the CUT would see these as abominations.