There Seems to be some sort of issue causing the game to crash on startup when Fossils is installed alongside TiCon, but the smeltery module is disabled. Have had success loading the game with Fossils when smeltery is enabled, and With Smeltery disabled while Fossils is not. Contacted TiCon about it and they suggested it was an Issue on This end. Figured since TiCon support was relatively new that they were likely right.

Crash Report: https://www.dropbox.com/s/j2k8al41frf5e3m/crash-2020-05-17_21.44.03-client.txt?dl=0