Those countries will not be allowed to profiteer off temporary Chinese losses and to support US aggression through inaction.
China knows that they're militarily powerless to help China defend waterways, so they won't make an unrealistic demand for them to use force. But ASEAN must help punish US aggression with economic means and send whatever support gestures they can, within reason.
If US is invading Taiwan and blocking China's trade, while a neighboring country is doing nothing and still trading with US, this is the same as endorsing America's unprecedented attack. The public sentiment in China will not let such traitor nations, members of a coalition of aggression, go unpunished.
Remember that China and ASEAN are increasingly looking like a single economic bloc.
So ASEAN will serve as a transhipment point for Chinese imports and exports, which suits China fine.
Remember that if there is trade disruption, it is China which has the production capacity, which the US (and the rest of the world) wants.
Prices for Chinese exports will skyrocket because of the shortages, which mostly benefits Chinese producers.
We've seen this story happen in recent years many times.
At a minimum, I expect ASEAN countries (excepting Philippines) to deny any resupply to US military forces.