I love coming up with ideas and creating projects especially if I can save few bucks buying comparable items. But, for me, anything used for inside a kettle.... I will stick to known items. Here is why. Not knowing the composition of the metal at hand, really hard to say if it is safe to use. That coffee can would have some galvanized steel ( maybe maybe not!). Zinc oxide fume can make you sick. That is only one case. Even with those cheap SS bowl, how do we know what it is actually made or have any harmful coating on it.
One time I used aluminum chicken wire at the bot. of the charcoal chimney that literally melted. There are lot of chemical reactions and fums given off. This is the same stuff people use to make custom charcoal baskets and other mods with.
Some of the steel stuff might be ok to use, but I want to caution on the safe side and stick to known items.