The books are based off of the games, and the games came first, so yes, each game (sadly) is canon.
nope. in canon Starkiller isn't a Force-god, but the game needed to seem fun, so they made the players feel epic. Canonically Starkiller is not all that the games potray him as. Although he is strong in the Force in canon, he isn't as strong in the books (canon) aa he is in the game (noncanon)