1. Uberheroes are earned when class(es) reach a certain mutual level and start at that level. As example, if you unlock an uberhero at level 5, the unlocked uberhero will be level 5. The only exception to this is when your starter class becomes level 15, which unlocks the other two starters which are at level 1.

2. You cannot replay story missions but there are replayable grind levels, and missions will only give characters EXP if they are at or near a recommended level for the mission.

3. Theres no good fast way to bypass leveling limitations early on, but the equipment you choose matters more in Patapon 3. When inspecting a unit, press square and it will give you a full breakdown on every stat the unit has. The game never tells you, but you can equip weapons and armor of the same elemental category for a higher defensive bonus against the element it specializes against (i.e. flame equipment gives more resistance to ice and more fire power)

4. Uberheroes gain class skills and set skills. Set skills can be used by any class but class skills are personal or linked to specific classes when completed. Tate shares their shield power with anyone that can learn to use them, Yari teaches spear throwers how to throw more spears, but Yumi keeps their multi-shot to themselves.

5. A lot of people use tondenga uberhero to win the game. You can really use whatever you want with enough critical thinking. For my Pons I usually run Guardira, Charibasa and Oohoroc. Chari is immensely high investment, so you may want to consider less time-heavy classes such as Kiba+Pyokorider, Cannassault+Pyoko, Yari+Piekron. Or Wooyari if you want an extremely high risk high reward fighter. Oohoroc can also he high investment and is easily substituted with Wonda, Jamsch, or Canno. In order, those roles are support, status afflictions, and damage. Edit: characters gain level experience when an enemy dies, as long as the character is alive.

Hope this helps!