Thank you for the replies. I plan on having a number of unique units for the board game. Each faction will probably have, at the least, one or two unique units, to set them apart from the rest (especially those of similar culture). I know a Roman era board game has been done before, actually, several times I believe. Britannia is an example, in that it includes the Romans as a faction.

I just wanted to add:

If you are using Lugoae for generic celtic spearmen then its the wrong name to use as that certainly isn't a direct translation.
Actually, I do realize that I made an error in assuming that it was supposed to mean spearmen. Technically, Gaeroas is the more accurate word to describe Celtic spearmen (it does mean "Spear Soldiers" which is close).