It was reported that the payroll tax furlough was the one area Trump was on solid ground.
Hard to tell without seeing the actual Executive Orders. The devil is in the details. All four may pass any challenges, but I doubt that they are as broad reaching as people might think. The eviction suspension might be limited to Section 8 housing, for example, since that gets federal funding. Student loan interest waiver may just be for students getting federal loans. Things like that. If that's the case then I don't see where any of that is outside Trump's authority as president.