A: No, she can't. First, there is no contract of lease, so there can be no eviction. Second, if it is true that you and she were both deeded the property, then you have every bit the right to the land as she does and she can't eject or oust you simply because she wants to. Feel free to contact me if you need help with this.
A: It depends on a number of factors, including but not limited to whether you have any prior criminal convictions. I would recommend hiring an attorney to help you with this. If you are a first time offender, you can probably avoid jail time and possibly avoid having a conviction on your record if you can abide by the terms of your probation. Feel free to contact me if you need help with this matter.
A: In short, no. Based on your question, I would guess that the person likely holds either a tax certificate or a tax deed (one may demand a tax deed three years after they acquire a certificate of sale, i.e. a tax certificate). In any event, they are not owners of the property in fee simple, and they therefore do not have the right to enter onto the property and change the locks without the owner's permission. You still have a right to redeem the unpaid taxes. This area of the law is fairly complex, and I would recommend consulting an attorney. If you are located in Mobile or Baldwin County and you feel like you need an attorney to assist you, please feel free to contact me.