part owner of C corp dies--what happens to outside investments

Situation: c-corp with 3 shareholders Owner A has 51% of the company's shares, therefore controlling interest company owns a fair amount of stock in company B worth about $2.5 million (Owner A's name and company name are on the account at computershare) company, without the company B stock, is worth about $3 million upon death, Owner A's company shares go into a trust with the 2 other owners having first right to purchase owner's company shares Trust then has controlling interest. Question: what happens to the stock of company B when owner A dies? 1) it should be counted as part of the overall total of the appraised value of entire company? 2) does 51% of stock from company B go into owner's trust and divests itself from the company when it goes into the trust or does company retain ownership? 3) can owners B and C use the stock to buy out owner A's company shares? In this case owner A's total worth in the company with the investment stock is $5,500,000 * .51 = $2,805,000 buy out price