Lewis has played mostly on the RW for us so Jack is the one in front of him at the moment. It sounds like Medina can play on either wing or at CAM. Both Harrison and Lewis have played both wings in the past. Ideally I think what this means is that we will have an attacking rotation. Best 10 would be Medina LW, Maxi at the 10 and Jack on the RW. To cover for call ups, injuries and just to keep players fresh have Medina as the back up 10 with Lewis and Wallace rotating through the wings.
Take all the time we saw Tommy last year at both LW and in the midfield, add in the 1-2 games Wallace played out of position in the middle, rest Jack a bit more often so he doesn't wear down and there should be plenty of time to go around between Maxi, Medina, Harrison, Lewis, and Wallace. This all assumes Harrison stays, fingers crossed.