Option #3 was a throwaway possibility, not really meant for actual use as it’s rather silly.
whatever && !is_bbpress() means, literally, that
whatever has to be true AND is_bbpress() is not true. The
! operator inverts the boolean meaning, so true becomes false and vice versa. If is_bbpress() is true,
! makes it read as false. If false, it makes it read as true.
By the way, the backtick ` that indicates code is on the top left button on most English and European characters.