It's not complicated because there is no conflicting guidance from the federal vs state governments. Once the federal government orders everyone to open up it will be unknown what the right answer is. States that want to continue with the lockdown will likely sue the federal government, or companies that want to open up would sue the state. The courts will weigh in and it will probably go "something something interstate commerce" and the federal government will win, forcing the states to open up.

After that it really depends upon how states respond and you could be stuck in a giant game of chicken. This is where it might get complicated and risky - mostly for people trying to abide by the law. Damned if you do, damned if you don't. But in this case, the government wont' really arrest you for not opening your car factory. But the state might arrest you for doing it.

In the case of Marijuana, it's really quite simple: everyone in California using marijuana can be arrested by the federal government. They just choose not to, at least usually.

ICE is a bit more complicated. They are trying to compel cooporation from local law enforcement, who is not responsible for enforcing immigration law. They aren't asking them to enforce it directly themselves though.