Without Lilac, ?-6 in particular will need an extremely high speed team in the middle, with slow teams elsewhere, or they won't reach the pest before the rest kill the boss and reach the flag. I personally keep one copy of each 2 and 3* for completion purposes, most of the 3*s have all equip slots and level 3-5 skills, so I shouldn't be hurting TOO bad in the Nation Battles (when do those come along, anyways?)