I am at a loss why you are importing the image into LR, then opening it in ACR to process the RAW data, and then using PS to add EXIF/IPTC data. This is the sort of work that LR is supremely good at, in fact it's pretty much LR's core functionality.
I would be importing into LR, and then applying all of the data to the images, actually you can set LR to add all of your personal data like copyright and contact details, as well as basic Keywords etc automatically on import. I do all of that as well as adding IPTC News Subject codes to all of my images on import to LR. All of this can also/additionally be done in the Library module. The other advantage of using LR for this is that it allows you to add data to more than one image at a time. I actually also use the Map module to add location data to all of my images.
I then use the Develop module to do all of my RAW processing. The LR Dev module has all of the same tools as you will find in ACR, although they are laid out a bit differently. Once you have finished processing your images, it then becomes very simple to export your RAW files in any format that you need. For example I have a preset for my local paper submissions that resamples the image so that it is saved at 2048 Px on the long edge, as an sRGB JPEG at 80%. You can also set the export module up so that it will save the image with variable compression levels, so that a maximum file size requirement is met. Most newspapers do not need full sized files from modern DSLR's, and resizing the image down to something appropriate to the use that the paper will make of the files also helps to reduce the finished file size.