A) The only stupid question is the one that isn't asked.

1) I think PoolDoc's reason is that dichlor dissolves quickly and is the quickest way to get CYA in the water, Trichlor will also add CYA but at a slower rate.
2) I'm hopeful that a lot of it has stuck to the cloud in your water and the new cartridges may help remove it. There are other methods to remove metals, none of them are fast. Refill is quickest - are you sure you can't?
3) It didn't just show up this year. Your ladder was coated in it from last year. The copper dookickey in the Krystal Clear was actively adding it to your pool.
4) You can put it in a sock and hang the sock in the pool, prefereably in from of a return, Squeeze the sock every now and again to help it dissolve.

-5- If anything I've written conflicts with or is contradicted by PoolDoc, - What he says goes.