I agree with most of what you said however I must urge caution.
I speak from experience when I say that some platters are made of glass!!!
Two years I had to destroy over 30 dead drives of varying ages. I dismantled the cases, removed the platters and cut them into small pieces with metal cutters. Admittedly I was on auto pilot by the time I got to the last few but one of them was made of glass. There was glass everywhere. The scary thing was it didn't really look or feel any different to the others.
If you do dismantle a drive completely watch out for the internal magnets. They are very powerful.
All the best