Ey clt2488 ! THANKS for your time! i already readed those URL you said, but those arent really clear for me 
what exactly a level blueprint is? From the documentation:
“A Level Blueprint is a specialized type of Blueprint that acts as a level-wide global event graph. Each level in your project has its own Level Blueprint created by default that can be edited within the Unreal Editor, however new Level Blueprints cannot be created through the editor interface” but you said “General game logic almost definitely shouldn’t go in the level blueprint” (i thought the same than you)
To me,reading the definition, a LevelBlueprint is a class that manages what happen in the world, manages when and why and how and where to spawn enemies,ships or other type of game logic. But i am not sure at all becouse of the GameMode Definition.
Lets say i have a blueprint/C++ Class created of a ship. But i have a Ship handler class that manages ships in the world. i would open Level blueprint, create an instance of the ShipManager and trough that i would instantiate a ship… is that correct? from this perspective, Level blueprint is like the Main function of that specific level.
About the question 2, if a have a class/blueprint i can add a variable, that variable can be a class or a Instance:
Class example would be: EnemyShip *myUninstantiatedShip; //the variable value is null or garbage.
Instance example: EnemyShip *myInstantiatedShip= new EnemyShip(); //the variable is different from null or garbage.
Going back to my question… if i add a Instance variable to my blueprint class. when i instantiate the class, the variable will ve different than null(AKA will exist and be instantiated) is that true?
Many thanks for helping me to understand those tricky things. i am a programmer to the core and dont really like the blueprint matter, i have to learn it forced 