Starter Set and 7 friends… any helpful tips?

If an Eldritch Knight is concentrating on a spell and uses action surge to make an attack, is the spell concentration broken?

Any reason Paladin multiclass requirements aren’t Str 13 or Dex 13 like Fighter?

Are or are rangers not supposed to get Advantage on attacks vs Favored Enemies?

Question: Are or are rangers not supposed to get Advantage on attacks vs Favored Enemies? I assume no cause Rogue exists.