Can we terminate employees if they refuse to take body temperature or wear masks?

Yes, UNLESS they advise they have a medical condition/disability that should exempt them.  In that case, you will engage in the interactive process (an open dialogue) to determine what the issue is.  If necessary, you will request that the employee provide medical documentation confirming the disability.  However, in light of the current executive order issued by the governor, I’d encourage you to speak with legal counsel if this issue arises.