There is an Anvil you can use on the second floor of the Foundry, however, you use Anvils for Smithing. Making an Amulet would require Artificing and a bench for it which is sometimes sold by the Goblin Merchant (the Amulet is a lvl 2 recipe). The Amulet can also rarely drop from chests but the probability is very low. I wasn't expecting anyone to sell it to be honest, as it is a very good accessory item to wear.
Frail fever should only transmit through infected bite, but it can last a very long time if not treated.
As for the Dyes, I suppose they might trade it to some other village for something more useful!
The puddles are just for show at the moment, they replace the little fireflies you see at night in the same locations. Though I may add some use to them someday!