Absolutely DO NOT do deadlifts after a full back/bi workout. I am assuming your are a complete beginner. If you only train 3 days a week your CNS won't come into play. If you can't finish a workout after doing deadlifts your work capacity sucks, but it will improve. Also, doing bicep work prior to deadlifts puts you at a greater risk of bicep injury. As a beginner a bicep injury is unlikely, but I prefer all injury risks are minimized. That's just me though.
And by your logic, deadlifts work your back, bicep, and chest so you can skip other stuff too. If you don't believe me, feel someone's chest while a deadlift is locked out. It is flexed. Deadlifts work your legs, but not that much. And eventually your back will become much stronger than your legs and you will be doing a deadlift with all back. That again puts you at a greater risk of injury. Don't be a pussy, train legs.
And by your logic, deadlifts work your back, bicep, and chest so you can skip other stuff too. If you don't believe me, feel someone's chest while a deadlift is locked out. It is flexed. Deadlifts work your legs, but not that much. And eventually your back will become much stronger than your legs and you will be doing a deadlift with all back. That again puts you at a greater risk of injury. Don't be a pussy, train legs.