Carter Page was already being monitored by the FBI before he joined Trump's campaign. George Papadopoulos plead guilty under Mueller's investigation, and now appears to be cooperating. Joe Schmitz left the Defense Department for obstructing an FBI investigation, and then started working for Erik Prince. Schmitz more recently was involved with a weird plot to get Clinton's email from the dark web. From the article:

He claimed a source he called "PATRIOT," an unidentified contractor he was representing, had discovered what he believed was likely material stolen from Clinton that could contain classified information.

And Jeff Sessions had to recuse himself from the Russia investigation for his role, including lying about meetings with Russian ambassador Sergey Kislyak.