A lot of variables to take into account in your question. Are they using RaF? Heirlooms? XP potions? And are you talking total time played?
There are many variables to take into account here. You have things like combat routines and how efficient they will work in random dungeons on lower levels. You also need to take into consideration whatever combination of classes you are going to use. As you won't be using any heirlooms or have any RAF going you should have a team of characters that don't relay on the same kind of gear / drops.
But one thing is for certain. Having a full five man team running on the same hardware ID, on the same IP-address is bound to get you banned rather quick. A year ago I manage to have a full team going for a long period of time, but trying the same these days and I'm normally banned within a few days.
that's not true.