I think there is reason to believe that S from the Palpatine conversation of May 2017 is Senator Sheldon Whitehouse- who is on the Judiciary Committee. See the graphics.It looks like Senator Whitehouse is the one leaking information to Louise Mensch. Notice how she gives a shout out in her tweet.

https://patribotics.blog/2017/05/22/mike-flynn-turns-on-trump-talks-to-fbi/

https://twitter.com/LouiseMensch/status/876917175507922944

https://twitter.com/SenWhitehouse/status/865662380100829185

https://twitter.com/SenWhitehouse/status/864952708482117632