Is it permissible for some of the inheritors, without consulting other inheritors or seeking permission of…

Answer

If they wanted to enforce the provisions of the will, this is the responsibility of the executor of the will and they have no right to do so without the permission of the executor. Yet, if they want to spend from the shares of the inheritors in the estate, this should be met with the approval of all the inheritors. Otherwise, it will be deemed usurpation of the shares of other inheritors.