Mr. Happy's advice is spot on (thank you for posting this).
On the US side, in addition to Linked In, there are lots of similar resources to those in the UK. This is great advice whether or not you retain your position or are given a package. If you're in the US, and you expect to be made redundant, then you should be working on this now because packages and notice here are much different than in the UK. The shorter the length of time you've spent with TR, the less you can expect. So, the financial trade off of stay or wait is dependent upon that. Even if you are offered a position to stay, you need to evaluate whether or not the new org or your new manager will be beneficial for your career. You may have a short term solution, but you need to consider what your long best interests are.
On the TR side, because there have been an increasing number of organizational announcements, including open positions (which then means other positions are being eliminated), there are fewer TR surprises when compared to the F&R side, where Craig has indicated that the org structure will not be announced until after the sale is completed. On the TR side, most I think have a good idea (or should if you stop and think about the future) as to their post-separation options.
On the F&R side, the F&R leadership has left everyone hanging. Craig can talk about how great the new name, brand, logo, funding, values, etc. are, but the lack of information as to how the firm will operate at this very late date leaves people to speculate as to the many possible outcomes there could be. Blackstone has publicly indicated to a number of news outlets that it will reduce costs substantially. This combination, Craig's absence of information, plus Blackstone's cost cutting projections, means F&R people need to plan for a change.
Waiting first for a package may be okay depending upon your situation. But since it takes time to find the next great opportunity, why not seek a new position while you're employed? Keep your options open. Take back some control in your life. Think of Craig as the Wizard of Oz. He wants you to see this all omnipotent, great figure and accept that he's some great genius. He's really just a little, rumpled man in a rumpled suit standing behind a curtain, desperately trying to figure out which lever he can pull to make Blackstone happy.