ResizeObjects rescales objects in X and Y, but not in Z. This means that you should be able to convert your object measurements from the downsized to the original size by multiplying by a factor of 4 for each dimension that was rescaled. For a measurement in X or Y only, such as AreaShape_BoundingBoxMaximum_X, you would multiply by 4 (1 / resizing-factor). For a volume, you would multiple the downsized volume by that factor twice, to account for the downsizing in both X and Y, but not Z.
However, we highly recommend making measurements on as-close-to-as-on-the-microscope an image/object as possible, so my first recommendation is to experiment with resizing your objects using ResizeObjects and then making the measurements on that resized object in combination with the original image (for intensity / texture measurements, etc). If your computer can handle making measurements on the original sized objects, that would be the preferred approach.
Hope this helps!