Investors & landlords

Thanks for your input. I was able to find the statements and determine the cost basis for shares purchased each time there was a dividend for a large portion of the noncovered shares sold. Still have 3 questions:

1) A large portion of stock sold was a result of a stock split with no basis reported, can I use the historical data for the stock price that day to determine basis?

2) I didn't purchase the initial number of shares, it was from a divorce settlement and have no cost history. Can I use the stock price the day that I received it as the basis?

3) What box do I use on form 8949?

Thanks