Yes, these details of the will just go to further embed this Robert in the family of his wife Margaret, als Kermeen, Ballig. Of the witnesses, R[obert] E[dward] Christian, Baldromma (1817-91, sea captain) was the son of the Edward Christian at the top of the message, and of Isabella Christian als Kermeen, Ballig, Margaret’s eldest sister. Robert Cottiman (1802-1848) was the son of Catherine Cottiman, als Joughin, elder sister of the one we have been calling Margaret senior, i.e. Margaret Kermeen, Ballig, als Joughin, and so a first cousin of Mrs. Margaret Gill.
Frances Coakley, in her posting of August 9th, tells us that Margaret Kermeen als Gill was buried at Maughold in 1843. So she could not have been the one alive and living in Liverpool in 1854 that Jean, in her posting of August 17th tells us is one of the facts actually known about the mother of Sophia.
Nevertheless, if some kind person carries out the further research urged by Sue, there could yet be a surprise twist to this story.