you must see a lawyer. if you try to sell it there will be a title search performed to see what documents are of public record. a lawyer can advise you on whether you own the property or not and what rights you have. whether you do it now or when you sell you will find out. better to know now than later. and to find out what your options are as they will narrow as time goes on.
without a detailed review by a lawyer can all the issues raised in your question be appropriately addressed...nothing in this response should be construed as establishing a lawyer client relationship..the answers herein are for informational purposes and not to be construed as advice
You are silent as to whether the deed was recorded. If not, you should record after discussing the situation with an attorney. Most importantly, if you know the transaction is going to be attacked by the rest of the family, you should, if possible, resolve these issues before any sale.