I really doubt anybody is going to plug the cellphone to a power supply (if the original battery is dead, I bet it is), use a program to crack the PIN or PUK, and extract your (I bet outdated) information.
Google the code found on the top of each chip, so you can know what it does.
I have read on this forum that some strange metals can be found on electronic circuits, and off course, the never-ending debate about the cancer and the Pb solder.
I think all of that is rubbish or urban legend, at least for small exposure. The only dangerous equipment I know is the beryllium isulation of the microwave oven's magnetron: When broken releases dust, that even in minimal ammounts cause severe long term effects to health.
About your cellphones... Use a particle mask if that makes you sleep better
. I have cannibalized lots of cellphones and nothing happened to me.
I guess if you destroy some of the chip pins with a screwdriver, you will render it more unuseful than it already is.
I think that doesn't interfere with the recycling progress, according to History Channel.
Again, with all respect, I think its a time wasting and unnecesary measure.
Good luck!!