Paasky, take your time. It is a lot to do and it shouldn't drive you crazy. 
Btw, have you placed some of the units already on the map? If not, make sure to get rid of thhose units like spearman, archer etc. It's only ballast for the game (might slow it down) and confuses players who look into the civilopedia. However, if you have placed some of the units on the map already and you think it is too much to redo all that, then don't delete these old units, as that will lead to a change of the units already in place (the CIV-editor is not dynamic in this respect).
Finally, great to hear that you have taken care of the early war vs. late war units "relationship".
Keep up your good work!

Btw, have you placed some of the units already on the map? If not, make sure to get rid of thhose units like spearman, archer etc. It's only ballast for the game (might slow it down) and confuses players who look into the civilopedia. However, if you have placed some of the units on the map already and you think it is too much to redo all that, then don't delete these old units, as that will lead to a change of the units already in place (the CIV-editor is not dynamic in this respect).
Finally, great to hear that you have taken care of the early war vs. late war units "relationship".
Keep up your good work!