“Congress may by law provide for the case wherein neither a President elect nor a Vice President elect shall have qualified, declaring who shall then act as President, or the manner in which one who is to act shall be selected, and such person shall act accordingly until a President or Vice President shall have qualified.”
I.E. Congress selecting one who is qualified - Hillary
No. The Presidential Succession Act of 1947 would apply. So we would go by the regular Presidential Line of Succession, starting with San Fran Nan. Of course, before anyone could become Acting President, after the VP, would have to resign from any other office that person held before such a person could become Acting President.
Of the remaining Democrats - who has the most power behind them/under their control?
I would say Hillary.
They’re not going to play by the rules. She’d politically manuever past Biden and Pelosi somehow if Obama was disqualified.