"Bostock can sell/merge Yahoo or get ousted. Those are his only two choices..."
Wrong again. There is Option 3. He can sit back and do his job, the way he has for years. He can hire a CEO, confirm with Yang that something can still be made of Yahoo!, answer questions from groups interested in parts of Yahoo!, decline any offers that are not outrageously high, create another poison pill to ensure the company is not bought out, and continue to milk the company at the expense of shareholders.