Yes, I would say they absolutely count, as long as you haven’t posted them here as their own thread already. (Showing off progress in the Snapshot thread or Quiltalong is totally fine.)
No, I think scraps that CAME to you are totally fair game. The tiles are from your home improvements, even if you didn’t install them yourself. And MightyMitochondria’s scraps were given to her by her mom. Also fair game.
Where I think I would draw the line is BUYING scraps to create something. The scraps should be yours from previous projects or something freely given to you. An example of something I think would be cheating the spirit of the Challenge, would be if I went to the Creative Reuse Store here in town and bought various bits of donated fabric, and called them my scraps. They would have been purchased specifically for this challenge. However, if I made a scrappy tote bag from my own patchwork scraps, and bought a piece of fabric there to make the lining, that would be fair. Does that make sense?