You don't get an 18% yield without risk. I'll take the loss if the deal falls apart.
I think the chances of the P/L closing are at least 90%. But it wont change my life if the dice turn up wrong.
After the recap closes, the preferred A will be a very secure piece of paper and a great long-term hold.
Other people have posted their views that the company will resume growth of 20-30% per year. In that case the returns on the common stock would be huge. But that's tougher to predict at this point. Maybe 50-50 as you say.