The reality is that there is no way on earth that Hunter is going to fully testify before either committee or privately without invoking the Fifth.
His plea deal fell apart so he already has cases pending against him, and that same prosecutor is not bringing/expected to bring more charges against him in California- tax related. And this is without even getting to all the other stuff that the House investigators are working. He has massive, massive exposure across the board. Massive.
Hunter and his attorneys are playing a much longer game which is to get some kind of plea deal back together again, which includes immunity on further issues provided that he truthfully testifies on the wider Camp Briben issues to be revoked if any of his testimony is proven to be untruthful.
Lemme tell ya. That is not what Joe and his handlers want. Not at all. You can cry the "Hunter is poor drug addict and everyone is picking on him" routine as the dem script requires but the truth is, he is a piece of shit who will sell the others down the river as needed to get a better deal for himself. Nightmare for the whole scumbag family.