Sorry for not posting sooner!
It is up to you whether or not you want to make 4 units using the same color. I would however prefer that you do not use the same fabrics for all 9 sets.
Quiltinghere, since this is scrappy it doesn't matter either way. Yes, just make the 4 units that you'd normally sew into a block and then don't sew them together. You can choose whether to use same fabrics(for each 4 unit set) or not.
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Hope this is clear, if not, pm me.