And if the whistleblower(s) does testify remotely, or with obscured identity, will the Republicans accept the testimony as real? OMG what a clusterfuck. They'll claim it's a set-up, "fake news," somebody hired to make up the story.
The only way out of this CF (that I see) is for a few more insiders to come forward anonymously. The IG said he was able to find confirmation with more than one person -- they need to come forward now.