I have very little knowledge in the matter, but since this is such a "weird" question for the non-FIRST world, I would think the best approach to this would be to setup a test.
Basically you want to know if the data transfer rate for the network will suffer because of the joysticks being connected, right?
Maybe use something like
this program to test the network speed and use some sort program or
page like this to test the joysticks.
- Run the network test with no joysticks
- run the network test with joysticks running and working (mash the buttons!!!)
I would probably feel good if the tests showed no significant difference.
-Leav