Edit to add 3 / Another option would be restart with the original history so people don't outright lose old coins, but make the new block reward such that the entire 'last known' coin supply on the old chain would be reissued in a few weeks or so on the new chain. That would make old coins worth very little but still something. That would need a block explorer though to examine the history roughly post 2019 to look for unusual surges in coin supply that might have been behind huc's early death.
How we build a "treasury" could address some of that, since if the old coins are valuable they ought to be able to buy a lot of stuff to put in the "treasury"; whereas if they are worth close to nothing they'll be able to buy close to nothing to populate their "treasury" and donations will be needed to get a decent treasury together.
It might not need to be worth much at first though so maybe supporters could start a FreeCiv civilisation among the "civilised worlds" that uses HUC as its currency, and have that civilisation put some of its earnings into the "treasury" so as the civilisation grows so hopefully will the value of its currency.
-MarkM-