I believe that for joinly owned assets that are sold, the proceeds and the basis are split with each of you taking half. I would take great care in evaluating if you really have a gain. Also, if you do, I would make sure that it is one that would be taxable before reporting. There are situations where gains are not taxable or may be deferred with proper planning. Don't hesitate to get advice from a professional. It may save you money.
This response does not create an attorney client relationship nor should the advice be relied upon because it is not specific to your legal situation. Before you depend on legal advice, you should retain competent counsel.
Yes. If you are married and jointly own the home the house is a marital asset. You may divide the proceeds equally. But, be careful. You may not need to report the income if you meet certain criteria. A quick talk with a Florida tax attorney may help you make a decision on the tax treatment. Don't pay taxes unnecessarily.
My comments are NOT LEGAL ADVICE. They are for informational purposes only. Actual legal advice can only be provided after you have signed an engagement letter. Answering this question does not create an attorney client relationship. Remember that without attorney client privilege you could possibly divulge information that can hurt your legal rights in the future. I am a tax attorney in Miami Florida. I can help you with your federal tax issues via a secure client portal if required.