Not much experience with cherry, but.... The sap wood turns orange as soon as it is exposed to air. When you sand it out, it is a lot of work to sand it down to white, but it can be done. I generally sand out any tool marks and tear out, and don't worry about sanding out all of the orange. Some times it can be kind of splotchy, but that does go away with time.
Turn thin: to me this means wall thickness of 5/16 or slightly less. Any thicker than that, and your risk of cracking goes up.
Cherry is not a good wood for smoking with your bar-b-q. Some people can react to it.
As for the black iron spots, any wood will do that when green, though you don't see it on the heart wood of black walnut. Hard to avoid if you are sharpening. I wipe down the tool with wet shavings after sharpening, and my hands as well. That metal dust will float around the shop for days, so it can drift. I also wipe down my hands with the wet shavings before going back to the wood.
I prefer warped bowls, so you can turn that cherry down to 1/4 inch thick, round over the rims for standard bowls, then when finish turned, put a couple of wraps of the stretch film around the rim, with about 1 inch lapping over the rim, and the rest on the outside. This is a really good way to protect the rim, which is the most vulnerable part for cracking. I do try to make the bottom the same thickness as the walls. Leaving it a bit thicker will cause uneven drying stress. Most bowls done this way are dry in a week. Dry enough to sand out in 2 to 3 days.
robo hippy