I haven't read all the posts in this thread, but I gather that your fuzzy fabric is actually bathrobe type fabric and designed to be lined, so you have that pretty well decided.
When you get fabric that is an all over like your little duckies, it is hard to figure out how big to cut your squares.
I am not sure how big your biggest duck is, but a five inch square should work well - - you will get different little ducks in each square (or six inches)
if you add the 4-patches in complimentary colors alternating between the squares, might I suggest 2.5" squares in your 4-patch, which would make the squares you cut = 4.5"
If you need different measurements, I can help you do the figuring <wave>