Alabama is one of the southeastern third world states. The maximum weekly unemployment benefit this person could be drawing is $265 a week for 26 weeks. That's not likely to be anything you could draw partial benefits with, unless you are really really being cut in regard to hours and pay, because in order to receive benefits, you have to have made less in gross pay for the week than the weekly basic allowance. I suspect that the company, with its good lawyers, will have carefully stocked the jobs to where no one qualifies for partial unemployment. They don't like to fool with it.
That being said, you have had a good run with this place. But the company is going to downsize and lower wages. They can, they will argue that they "have to" to stay open. (We all know it's to get rid of you guys, the long termers, the high earners, the "blue hairs" as one company exec actually said.) The question is, are you going to be able to replace this job with anything at all that is better than what you had? If you are in a small place, with limited job opportunities and you've had the best place in the area to work, you are going to have a very hard time finding anything equivalent. As long as this place will continue to offer you something other than a lay off slip, they might be doing you a favor.
Particularly in states like Alabama, with very low weekly benefit amounts, unemployment insurance is not a lifestyle choice. It's a bottom of the barrel very low paying necessity, and it ends VERY abruptly after about six months, with NO potential for any extensions, regardless of whether you've found another job or not.
So if you refuse to accept any of these lesser jobs, (IF they're offered to you instead of a separation notice) you are let go, and apply for unemployment insurance. The chances are fair that you will be approved, and you draw until about next summer, without finding anything else, but then what?
These new lower paying jobs at this old place may look pretty good to you after you've been shopping around the area for other jobs. This company may eventually shut its doors altogether. Then there will be more people out there competing with you for other jobs. You people who've had the good jobs with good wages may find that employers shy away from you because they'll think you have too great an expectation of being paid well and having decent benefits. Sad but true.
No, they can't make you take much lower paying jobs with this company. You're pretty likely going to be able to get approved for unemployment insurance, though it will be a long process to get it adjudicated and start receiving weeks of benefits at max $265 for 26 weeks. They'll deal with how much severance will affect the unemployment, you go on and file the claim immediately, tell the system about any and all severance you are receiving, and let them make the decision.
Warning, the job you are now doing is the job you will have to consider yourself "able and available" for when you file a claim. You mention that the new job with this company you now have is more physically demanding than your former jobs. BE SURE you do not in any way mention any physical limitations on the type of work you can do while you are in the unemployment process. If you were to quit the new job you're working now because it is causing you problems related to your health, you would not be at all likely to be approved for unemployment, as you must be fully able and available for equivalent work.
Then what? No, "Unemployment can't make you take something that was less than what you were making" technically, but realistically, are you going to find something that will be equivalent to what you were making? During the time period you are drawing benefits, you may have to really lower your expectations. You've had a very good job that will be hard to replace. By the time you have drawn out your claim, you are expected to be a whole lot less picky in your demands about what kind of jobs you'll accept. And you'll need to be. Because as I said, that unemployment will come to a screeching halt, and there is no more until you've worked again and paid in more quarters of wages and been laid off through no fault of your own.
So you have to make a decision. If you accept the new, lower paying jobs, and work one minute at them, they're now considered the ones you'll be laid off from. If you accept one of them, and later quit because you can't live on what you are making, or because you don't like the working conditions, or because your back is hurt, you'll probably not qualify for unemployment insurance at all.
If you want to go ahead and refuse the jobs, and take the lay off, file for unemployment immediately and take what you can get. I know you understand that you'll have to find something else, quickly, and it probably won't be as good as what you had, at least to start. My best wishes to you. I have spent many years working with people in this type of situation. It is a hard change, and the reality of losing a good job is very tough. But sometimes these changes we are forced to make turn out well.