Investors in the unicorn know it's a ridiculous market cap, but will lock in preferential payout on the exit.
This is not a thing that happens in the vast majority of circumstances. Preferences are for downside protection not a way for investors to actually make money. No one invests with the goal of making use of them.
#2 is not at all clear. Investors lost (collectively) over 125 million dollars. The only employess that lost money are those that exercised stock options and had to pay taxes on unrealized gains. It's highly doubtful that this totaled nearly as much as the investors lost.
This is not a thing that happens in the vast majority of circumstances. Preferences are for downside protection not a way for investors to actually make money. No one invests with the goal of making use of them.