And how do we know that China or Lam wouldn't just lock up the "leader" after all this is over. They have proven themselves to be quite untrustworthy when it comes people who might be considered leaders of this movement since the handover of Hong Kong to China.... even threatening some of them with death.
Yau Wai-ching and Sixtus Leung
And another lady (much older) who has been protesting since the handover (can't find her or the video of her.)
The brokers are those demands as long as people stick with them.
We could potentially have a previous person that acted like a leader to come into the negotiation table, with protection and publicity to settle things. But that person, in no regards will consider him/herself as a leader.... only as a information relayer.
We can also have an official from the other Asian countries (Japan? South Korea start the negotiations on behalf of the Hong Kong people, but again, "China stop meddling in internal affairs of the country."