Can EBV cause a devastating immune response in which it attacks the nerve cells and peripheral nerves causing an all or none situation?

No, not really. First, realize that most adults have been infected with it; therefore any disease at all from it, even mono is uncommon to rare. Second, EBV can only infect lymphocytes it rarely involves the nervous system and although the very few articles don't say it, its due to the immune system attacking the nervous system not the virus. http://www.ajnr.org/content/27/7/1447.full Your pattern not described.
Please elaborate. What do u mean by all or none situation.