Maybe I'm reading the context of your article wrong, but as far as I can tell, there was no funding of Republican campaigns either directly or indirectly through Schiff. They did some advertising which I think is shady to disregard the other candidates and only frame it between Schiff and Garvey, but I can't find any evidence or articles directly stating that DNC or Schiff money was funneled into Republican campaigns. Even Porter didn't make that claim from what I can tell.

Here's the breakdown of the campaign contributions and spending: https://www.opensecrets.org/members-of-congress/adam-schiff/

So what he did was shitty to the other Dems hoping to be on the ticket, and it worked because it edge them out of the race, but there was no direct contributions to the GOP candidate.