From my vantage point, this is much ado about nothing, given the fact there's a POA and Will in place already for the 108 year old mom (and God bless her soul having gone through the Spanish Flu of 1918, the Depression, WWI and WWII, Pearl Harbor, the Korean War, Cuban Missle Crisis, the Civil Rights Movement,9-11, the Vietnam and Afghanistan Wars, etc.) She's living history and I hope her children and grandchildren take the opportunity to record her thoughts and experiences as she is still lucid. (We know a 103 year old gentlemen, still lucid and mobile, who was a Marine and served in the Guadalcanal Campaign during WWII, and he is always anxious to tell his story -- if you don't prompt him, he'll actually say to strangers "don't you know I'm living history.")
But back to why I believe this is much ado about nothing.
Our Centenarian wants to leave the house to one daughter, doesn't want the responsibility of owning the house anymore, and wants her assets and valuables to be divided equally among her children. The first isssue of leaving the house to one daughter is solved by simply amending her will to say that (and if she's in a state where probate is easy and real estate drops like a rock to a designated heir, probate accomplishes this in a very expeditious manner -- the will when filed operates as the transfer document. The second issue - the Cenenarian not wanting ownership responsibilty over the house is already solved by the POA currently in effect and the fact that the daughter in the house is maintaining the house and paying taxes and insurance. What else needs to be done there, except explaining that Mom is now out of the loop and children are taking care of the house.
The final issue, like the first one, needs to be resolved by amending the Will, making sure all assets (including insurance policies such as naming the estate as the beneficiary or if not doing that, then equitably adjusting beneficiary payments) go through probate, and equitably dividing the proceeds and assets, especially appropriate if funeral bills, medical expenses, and assisted living facility expenses have to be paid -- you really don't want to be scrambling around for this if all that's left (as currently mentioned by OP in the estate is the house) -- how are bills to be paid after death and how are refunds (such as tax refunds) to be handled!
Sometimes the idea of avoiding probate makes no sense, especially if you're not in California where probate I'm told can be a pain, even for small estates.
The OP needs to get competent counsel to work with the familiy on this and stop taking advice over the internet, including advice from me,