The unfortunate part of it is, I don't think there's any quick way to separate Trump from any foreign underwriting. I think he'll have access to as much as he can spend as long as there's any significant chance he can win.
The down-ticket candidates on the Republican ballot will take the brunt. Trump's burning it all down, before he's dragged away.
At the end of all this, I half expect the biggest joke of all. If Trump can ever wrap his mind around the damage he's caused the Republican Party, you know he'll claim he did it for the Democrats.