Finding an early copy of Olaf is the most likely reason to force this comp but if not, just swap him out for another Bruiser or Warrior until you find him. Bruisers are a strong start and the easiest way to save enough health for later. Level up to 4 at stage 2-1.
You'll start rolling at level 7 so you should start to use the units from the actual team comp. All of these should get to 2 star pretty fast once you do roll. Level up to 6 at stage 3-2.