Personally - I have found that the best way to handle any situation is to be honest. You never want to "bad mouth" a former employer/employee in any way because the world isn't as large as we think, and you never know who knows who, etc. But also - you don't want to be viewed as a negative person, the type of person who is going to talk the same way about their company should you eventually be employed there. Keep everything positive.
In any case, don't be afraid to shed light on your current situation. Whether those are just rumors or not - this is simply the case of someone looking out for the continued development of their own professional career & aspirations, as well as their personal obligations (potentially family to think about, etc.). Letting a potential new/future employer know that you have a sneaky suspicion or feeling that things are going to change within your current environment is nothing to hide. Just don't make it the main/only focus of your search and why your open or interested in speaking/interviewing with them.
If you think that your New Potential Employer is going to use that potential lay-off/acquisition to their advantage in terms of low-balling a potential offer, it's not likely to happen. If you demonstrate your skills, value and overall benefit/need of hiring you - you have nothing to worry about. You have to be able to talk the talk and walk the walk right?
If you do go through the interview process and get an undervalued/low-ball offer, then that is probably a real good indicator that it might not be in your best interest to work at that specific organization now or in the future (as you are less likely to get raises, less likely for them to appreciate you, and maybe they aren't as sharp as you think they are). That is the same type of company that you are going to have a heck of a time growing with.
Having a job now - where you collect a paycheck and haven't gotten a notice - is an easy point to bring up should the offer come in where you don't want it to be. If they can't understand that, even after you are bringing that up, and they hold strong...then you switch over to the whole concept/idea that you do have several other things going on at this time that you are exploring, etc... and that you kind of want to see through before making a decision.
Bring up the point that you take your Career & Job very seriously and that you view it as a Marriage. You want both sides to feel like you need each other. Personally you want to be happy with where you go to work everyday, who you work for, and that you feel like you earned that paycheck & it's fair... but at the same point they are getting the right individual for the job, the right value, and someone whom wants to Grow with them.