Can you and your family non-rev on EK anytime you want?
If - (a huge word in this case, 'if') - there's a seat available. They frequently are not. Jump seat for family (or yourself, or another pilot) is an absolute no-no - unless you're management, and then the impossible becomes possible.
The load prediction page on the crew portal can all too often be near to useless, as it can often bear little to no resemblance to the actual load.