I don't see it as complicated at all to create an estate plan that would guarantee one heir a year of residency before a property could be sold, nor would such a provision require that the estate remain open or be difficult to enforce. It is also not necessary for such a provision to require rent payments, although if possession is exclusive it would be appropriate for the estate plan to at a minimum require the person with exclusive possession to cover the costs of the home during the period of exclusive possession. Insurance should be no more complicated than in other common arrangements, such as a life estate or tenancy.

There could be issues of resentment if siblings feel that one sibling is benefiting disproportionately from the estate while their inheritances remain tied up in a home reserved to that sibling's use. If she chooses to go in that direction, that's something for mom to discuss with the other siblings during her lifetime, along with consideration of how inheritances might be made more equal during or at the end of that year.