what can cause a constant rattling noise when the vehicle travels over bumpy road? on 2000 Honda Odyssey

Both front strut assemblies and both rear shocks have been replaced. In addition, both sway bar links and control arm bushings have been replaced too.

A good physical inspection of your steering and suspension should reveal where a noise is occurring.

My guess would be that you may have a strut mount with a worn bearing causing some noise. Just a guess.
1 more answer
Very likely that a strut mount is bad. If the strut mounts have been replaced, I have seen the actual spring seat break and cause noise as well. May have to disassembly the struts in order to pinpoint the location and cause of the noise