A: This question was posted in Arkansas Real Estate but from Kansas City, MO, my answer is based on assumption this real estate is located in Arkansas.
There is no duty of the prior owner to offer the property for sale to the tenant so there is no violation as to that matter.
As to the matter of the new owner wanting you to sign a new month-to-month lease, there are a lot of variables. If you have an active lease it should still be enforceable to the new owner. It is possible that your lease addresses future transactions and voids if sold or some other variable.
Without reading the lease, assuming it is still active, it is very difficult to answer your questions. I would recommend seeking a real estate attorney's advice, licensed to practice in the state of the property.
A: Arkansas does not have any statutes that relate to prepaid rent. That being said, if the reason for not being able to stay in the lease is related to military, you may have protection for refund through the Servicemembers Civil Relief Act. You could also be able to offset any prepaid rent if lease allows for subleasing or other remedies.