I am a big believer in prewashing and I do it exactly the way you describe, I just throw the fabric in with my regular wash, warm water and fragrance free soap. I don't use dryer sheets, but I do have wool balls.
I use color catchers (I did tests with the ones that I found at the dollar store and they were fine), and I do pretest fabrics I'm worried about by dunking an end into a white coffee cup and boiling water and see if there is any immediate bleeding.
After prewashing comes ironing, and I do not like to iron! I find I don't want to deal with much more than about 6 yards in any given load.
I don't buy or wash jellyrolls, just don't want to mess with them. I'll wash odd sized scraps, but I think the worst in turns of getting twisted and knotted up are old style 1/4 yards. I do put the smaller, odder, and long and skinny pieces into lingerie bags.
After washing and before drying it is important to take out any snags/knots in the fabric and I like to give them a good snap! to set the fibers in place. I dry until just before full dry, take out the fabric neatly and try to iron as soon as possible there after.