Will the right of survivorship exclude the old deed or should my wife and I prepare to lose the home?

Presumptively, your wife automatically ascended to title the instant your mother-in-law passed. However, her siblings may seek to set aside the deed as the product of undue influence or having been made at a time when mom lacked legal capacity to execute it. It could be a long and messy bit of litigation.

You have left out several important facts that prevent us from giving an answer. In what state is the property? What does the Trust say about the property, was title to the house ever placed properly in the Trust, was there anything in the Trust language which would allow the property to be taken out of it, what effect did her husband's death have on the Trust and property, when she put your wife's name on the property did she know there was a Trust so you can argue by making the transfer of title she dissolved the trust, if she said she would compensate you for your help by giving you the house you can not enforce that as a transfer of title to real property must be in writing but you may be able to sue for the value of the work you did, did you pay for any of the repairs on the house so you can claim a right of reimbursement for that, how much equity is there in the house, is there a Will, did the Trust language prevent her from transferring the property out of the Trust, was anything done to show the Trust was dissolved, who will probate the property, etc. ?You need to go to an attorney to review all these issues, and more, to see where you stand; then you probably should sit down with all the other siblings and tell them how much of a burden it was and what it cost you and none of them did anything and then tell them why legally you would win title and are they willing to spend a large amount of money on an attorney to fight you when all they individually could get is 1/4 of the equity less costs of the sale [house may have to be fixed up somewhat so can sell for higher price, etc.]. You have to consider if you are willing to settle with any of them and for how much.