Strictly going by the rules,even the person having counter ticket which is waitlisted shouldnot enter the bogiey.But in practice they do.(meanwhile if the berths are vacant ,tte will give them seat).
Similarly all 4 of you can board the train.all the members will just tell you the rule that you can't board.(That is strict rule,for all waitlisters nothing to do with e-ticket).
So in practice you all 4 can definitely board the train,but you should not disturb others.But how you all 4 people will get accomodated on 1 berth is your work.Moreover...
more... if berths will be available tte can allot you extra berths may be 1,2 or all 3.
Carry on ur journey