It's too bad you're not using Nova on your S6, because I would make you the MS icons as PNG files that you could use.
Now, I don't know if this exists ... but if there is a "stand-alone" app that you can install that lets you customize your app icons individually, then you'd be able to use the icons I can make you.
Just let me know if you want a set of the MS app icons ... and specifically which ones.
EDIT TO ADD: Also, if you want them, do you want them "square", or "cut-out" of the square mold and transparent around the outside? If you were using a black screen background, this is what the two styles would look like ... on the left is the "cut out", and on the right is the "square"...
http://i1130.photobucket.com/albums/m528/wiggum333/MS_Office_App_Icons.jpg