Importing Data From Y-up System

I have a bunch of scene data exported from Unity that contains meshes as well as objects that use the mesh. Much like blender, I have the local position, rotation, and scale values for those objects.

Because Unity is Y-up, everything looks super odd. Much of the stuff I see about converting from Y-up to Z-up says to rotate everything around the X-axis -90 degrees. But what does that all entail? Do I rotate the mesh vertices individually? Do I set the rotation on each object to 90 degrees less than it is? Wouldn’t that break when setting up parent-child rotations? What about normal/tangent values? Do I need to invert all X coordinates? I’m really having a hard time wrapping my head around all of this.