If the pieces in the 16 inch blocks were fairly big, I would take them apart and either redo the pattern or find another pattern that I could cut them for.
I do not use a seam ripper, I use my little pointed thread snips and snip every 3-4 stitches on one side of a seam and then pull out the thread on the other side. I think it causes less distortion and once ironed, the pieces are almost as good as new.