A bit of food for thought. Who is buying? A mega corporation that wants more diverse subsidiaries, a competitor or a private equity fund? These three scenarios go in order from less to more dire. In scenario 1, nothing will happen for a while and position elimination is not initially likely. For some mega corps that may take five years or more. Some holding company types have propensity for cutting benefits: vacation days get cut, insurance gets skimpier, 401(k) match drops, and so on, which results in some employee-initiated exits. This takes care of headcount without layoffs and expense of severance pay. Competitor buyout - layoffs likely after merged management decides who is "redundant". Can be as soon as 6 months post deal close. Private equity? RUN AWAY - NOW. The new management is likely to can all bonuses, walk a lot of people out of the door, and deny any severance pay. These entities exist solely to extract value out of acquisitions, nothing else, and the news for employees is never good under those circumstances.
My advice would be to start looking or, if you have FU money, prepare for exit whenever conditions get to you. If you really liked your job, staying would be optimal in scenario 1, but it seems to me that you aren't enamored with it and would be facing unpleasant conditions at work without guarantee of a bonus or severance pay in either scenario.