It should open up to team 6 for everyone when their mains' level is high enough ?

and medal 1 and 2 opens for Jonin medal.

Hmm.

If you are talking about the Team Slots being hidden above your screen then no. I do actually have the same problem and it is because of the resolution of your screen. Like mine, for example, the top part of some interface of the game is hidden above. The Character Images in Ninja Assist when choosing a Card and the Second Nature Skill selection at the top part of the Skill window, and what I've been doing to check or select things from there is to change the orientation of my screen. Sad though :|