Can't you set up some sort of foreign subsidiary to do it for you? Apple already uses this model for storing icloud data in china, to comply with chinese laws.

A presidential order is not a law, and if unconstitutional like this one, never has to be obeyed anywhere.

People regularly go to prison for violating US trade sanctions. The majority of Apple's employees including all of their executives are in the US and easy to find. I doubt any of them are volunteering to test the boundaries of US trade sanctions.

It depends on how intense the law/sanctions are. Example, no US company can trade/do business with Iran,even indirectly. The Trump administration also made it difficult for other countries to do business with Iran, makes it almost impossible for any other country to business with them.Hence, Iran's economy is in the toilet, and it can only trade with Russia, China and the middle eastern countries they have high-influence over(which are typically poor). Their oil can be sold to western countries, due to OPEC, but money that ends up in foreign accounts are inaccessible.

Plus, most of Trump's policies of late with China has to do with the new Silk Road. The new Silk Road is seeing China expand(land grabs) into other countries, and take over strategic points. Since, a lot of China's economy is from foreign trade, the more US makes trade difficult the harder it is for China to expand. Time, will tell if this strategy works or not, when China becomes the #1 superpower/economy in the world(speculation, but is looking more likely).

I am willing to bet the App Store is an Ireland based entity with contracts back to Apple to provide service aka generate expenses for Apple's US entity. That way Apple can book all the app store revenue in Ireland.