Hi, My name is XXXXX XXXXX I’m happy to assist you with your question today.
The concerns you have in this matter have to do with contract, or more specifically, what exactly are the specific terms of 1) the potential sale (which if I'm understanding you correctly you couldn't know because the division hasn't been sold yet) and 2) this re-hire agreement with your current employer. To answer specifically:
1. Does the buying company have to offer carry over seniority with employment relative to a right to severance? -- No, not unless it agrees to that specifically with you or your current employer as a term in the sale.
2. Does my company have any obligation for my seniority under the Re-Hire Clause if not stated specifically in the contract. -- No, not unless the re-hire agreement specifically states you will maintain seniority in the position. If it doesn't guarantee maintenance of your seniority, then seniority is lost.
3. Why would my company write the contract with re-hire if the buyer does not elect to employ at closure of sale....... would I not still be an employee of my company with historical tenure? Why a re-hire statement I this area? -- I can only speculate as to this. I suspect that they believe you will leave now if they don't offer you some security into the future. And your leaving perhaps would have a negative impact on the sale. Often times an acquiring company will need key personnel from the prior owner to transition operations. If you do end up stating with your current employer without a break in service, then your seniority is maintained.
My final thought to you is this, regardless of whether this new company picks you up or you end up staying at your current company, you will remain an employee at will. So at any time they can still terminate you. The only security you do have is that, if the new employer hires you, then terminates in six months, then current employer has to re-hire you...but it doesn't state how long they have to keep you on...so they could re-hire you, then terminate you in a month. My thought is that the re-hire agreement really offers you no security in the long run absent your faith that they will "do the right thing". Unfortunately, there is no legal requirement that this or any employer "do the right thing".
I believe this answers your question. However, if you need clarification or have follow-up questions regarding this matter, I will be happy to continue our conversation – simply reply to this answer. If you are otherwise satisfied with my response, please leave a positive rating as it is the only way I am able to get credit for my answers. Thank you, XXXXX XXXXX wish you all the best with this matter.