In this case WFH really is for your benefit, for multiple reasons: staying away from people (eg not get infected that easily) and keep your salary be keep working.
In that case the company should not be obligated to pay you. There's a good chance your employment contract contains a clause allowing your place of work to change at any time (within a certain distance of where it is when you join).
Perhaps not, but in California the company is never obligated to pay you except for labor you've already done.
> There's a good chance your employment contract contains a clause allowing your place of work to change at any time (within a certain distance of where it is when you join).
In California, you don't have an employment contract period. Even if you did, I doubt the requirement to (for instance) maintain an Internet connection at your home so that you always have the ability to work from home would be an enforceable clause.