I have a Douglas family, Daniel Minay, m at Braddan 1850 Elizabeth Kneale (b ca. 1825, younger sister of my great-great-grandmother Ann Allen nee Kneale), and d before 1862 leaving children Margaret (b ca 1852), Catherine Ann (b 1854, m James Harland of the Harland and Woolfe shipbuilding company), David (b ca 1856), Elizabeth Jane (b 1858), (John) Daniel (b 1859) and Frederick (b ca. 1861).
The names make a partial match with those you give. Do my dates sound about right? I have gathered these from the IGI and the 1861 and 1881 censuses, so there could be others that I have not picked up. The big age gap at the end is worrying. Was your grandfather Fred much younger than the others?
See also my posting in May 2000 further up the thread. Does Minnie Minay mean anything to you?