Wish you had found the answer before seeing this, me from U3D in late 2015, and have been working on game-devs with UE4. And you may find my comments(answers) to your questions:
- Tweaking projects from UE4 template projects about First Person Shooting and Third Person Shooting in both Cpp and Blueprint forms. Next, you may refer Shooter Game from Learning column on Unreal Launcher to figure out how to work between Cpp and Blueprint.
- You should mainly get answers from Epic official documentation on reflection system of UE4, UE4 framework (gamemode, player controller, player pawn, player state, game state and level blueprint), as well as the quick guide for programmers.
Practice makes perfect.