-Yes they're the same thing more or less but tabletop can include card games and boardgames too. While Pen and Paper refers specifically to stuff like D&D.

-Outside of combat only if you want it to be.

-Yes although depending on the dice roller used it maybe confined to a separate site.

-you roll for fighting and actions that would be spiced up by the chance element. 

-Depends on the rules and the GM. At the most basic it's binary pass/fail. However you can have failures that let you do what you wanted to do but add a negative complication and others measure your degrees of failure or success.

-If it's as simple as that then yes, maybe

-Depends on scope and focus of the game. However if he tries and fill every little detail than he needs to write a novel and not a game.