As long as your assistant’s system and your system have the same audio plugins (or use the Avid integrated ones), it should work. Same goes for the default Avid video effects. Most of the effect and timeline specs were massively upgraded when Avid changed from 5.5 to 6.0, so you shouldn’t encounter any problems. The only critical thing would be v7 bins, but since your assistant uses 6.5.4, I don’t see a problem there aswell. Happy editing!