Wrong.

Magnets won't affect flash at all, it can though mess up harddrives and also the touch screen and accelerometer will produce (almost) random data, but it shouldn't hurt anything.

the beep noise could come from a chip or a condensator which is slightly overused, so maybe that's why the iPod doesn't get to boot b/c it just cannot power the processor enough (just a guess)

also it could be that the firmware or boot-process is interrupted at some point, i don't really know if itunes restores that too.

but what i think is that someone sat on the screen or broke it somehow which may also have damaged some parts.

what you can try is opening it up and look for burned/extremely hot/cracked parts