I'm afraid the wash faded the Sharpie designs considerably, even after heat fixing it. Here's the before and after pictures.
There was also a small amount of bleeding to the back of the T-shirt. I'd definitely recommend washing anything dyed this way separately at first! I'm a bit disappointed at how it faded, but may still try it again. They traditional tie-dye that I did (a kit from the "Jacquard" company) washed up really nice and vibrant, with no fading at all!
With all the hot weather that we've had, I'd been more inclined to stay inside in the air conditioning and work on sewing and other things. Yesterday I made 2 more thread storage bins. Now all of my thread is stored nicely inside of these boxes. It was nice to dust off the spools and know that they'll now be kept dust-free. I discovered duplicate bobbin colors as I sorted them all onto their matching spools too. I now have 2 empty thread racks and bobbin cases that I can find new homes for!!