I’m not sure what you mean on sources. Pizzagate was mostly pushed through social media, but the claim was never about Clinton running a prostitution ring. It was more about the larger narrative of the reality of child prostitution rings, which sounded very salacious at the time, as even in Britain at the time there was a ring uncovered connected to politicians. Pizzagate started from a number of questions surfacing from Podesta emails (but no link to Clinton), but the story that ran in everyone’s minds to make it seem too silly to be true was the idea of Hillary running a prostitution ring (which was never the question).
And, yes, the Jeffrey Epstein issue was connected in this because the larger context was the reality of child sex labor and the idea of pizzagate was only one question within that larger idea, and the out-in-the-open behaviors of Epstein and co. were on full display but overshadowed by “lol hillary running prostitution rings lolz stupid repubs!” Hence my largest concern with Trump was an active case against him and Epstein that was, or should have been, common knowledge three years ago but now fastforward and it’s “what? Bill rode the Lolita Express 26 times? Who kept this knowledge from us??!”