>> I think there are really two sources <<
Many more than just two, IMHO.
Here are some of my hypotheses —
1. Bannon and Miller and Julia Hahn leak to undermine Kushner and Priebus
2. Kushner and Priebus leak not only to undermine Bannon and his faction, but also to undermine one another.
3. Kellyanne leaks to maintain her friendly relationships with the mainstream media.
4. Spicer leaks as revenge for Pres. Trump’s shouting at him during staff meetings.
5. DoD folks leak to undermine OMB director Mulvaney.
6. SecState T-Rex & Gen Mattis leak because Bannon, Miller and/or other WH staff keep them from choosing their own deputies.
7. Pres. Trump leaks to keep his internal WH adversaries off balance.
8. The Russian intelligence services create false, over-the-transom “leaks” that appear to come from within the WH and the various USG agencies.
9. The USG intelligence services leak as revenge against Pres. Trump’s criticizing them.
10. Sarah Huckabee leaks in the hope that like her dad, she can eventually land a music gig on FNC.
Have the “three WH staffers” been fired yet for leaking?