Since it's stainless steel, it should be, but I just let it soak in warm soapy water and it came clean.
#4 Has anyone used an alternate stainless steel or enamel lid with this? I already have too much aluminum in my system to use foil.
I use parchment paper. I have to avoid aluminum too (doctor's orders). I've used paper bags, too.
#5 Does the rack attach to the pan somehow to keep it secure?
The rack simply sits inside the pan. Roasts and chickens and turkeys are quite secure as they hang out in the oven cooking. No need to attach the rack to anything. Gravity is sufficient.