by JBMoby
The game is certainly playable with one missing from a race since the total number of tokens are only used with certain abilities.You can substitute a "lost tribes" token for these armies if they come up and that last token is needed.
I don't believe this will even be a problem with the skeletons since they have spare tokens for their ability.
Edit: Definitely try contacting days of wonder. Most game companies are pretty cool about replacement pieces like tokens and usually only ask you pay for postage and some change.