The classification of units only serves the purpose for the ai which unit to build. Setting a classification that doesn't fit the real function of a unit is a way to determine the ai's recruiting behaviour.
Well, i have made the daring move to try by myself if the alex-pack that you have in your sig can be used to continue a savegame and by now i have not encountered (unsolvable) problems. But i think night battles are not retroactive although the respective traits seem to be.
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