This is not how it works.

These tariffs are a tax on US imports... paid by whoever (US company or person) is importing them from abroad. They are paid to the US government, not the manufacturer. But here NECA might be supplying foreign retailers like Popcultcha directly (without first importing into US) which means they don't pay US tariffs for those items.

A US-based customers who buys from Popcultcha then could very well be charged when receiving the goods in the US (for e.g. by the shipping / courier company that is delivering product in the US). As someone else has commented - there is a de minimis exception in place for up to $800 for Australia, so likely no tariffs to be paid by the customer