The only reason GOP leaders ever opposed Trump is because they thought he was over the top with the dog whistling & base pandering. Too obvious. It's what they've been doing for decades, anyway, just with greater subtlety. Now that they know it sells they're all for him, of course, because he's with them at the level of policy, leading the charge in top down class warfare. Everybody but the Rich will be poorer when they get done with us including the govt.
Pence wouldn't have anywhere the appeal of Trump to lead them into the midterms & beyond so they'll just try to make Trump's problems go away by discrediting anybody who might reveal the truth. If Trump can purge the FBI of integrity they'll be able to exploit that themselves even after he's gone.