What's the best way to manage iterating on your base mesh?

Hi, I’m making a character for a game. All the characters use the same base humanoid mesh, but I add additional features like ears and tails to create the final model that I’ll use for each individual character.

My question is - how do I manage iterating on that base mesh? Like if product comes back with a new belly design how can I make the new design once and automatically share it between every character?

Thanks in advance!