Just came across your post of Oct 2008. I realize your posts are quite old and you may have discovered answers to your questions already.
Regarding Edwin Siddall & Family:
The family that has been given in the ship list came from Oldham Lancashire. Edwin and Annie, however, were born in 1877. The children: Harry, Edward (possibly Edwin), Nellie, and Thomas were all born in England. Ella, born 2 Oct 1908 in Saskatchewan. I believe your Edwin Siddall did arrive 12 Oct 1903, with the rest of the family following the next year.
This family travelled with Edwin's brother, John William b. 1872 Oldham Lancashire. I have not been able to find John William's ship entry into Canada.
The ship list that contains Annie Elizabeth with Ellen and all the chldren is a combination of the two families. There seem to be some children missing and some mistakes as well.
The families are Ellen 31 married (Missing children - Elsie b. 1895, Richard b. 1903) married to John William, Edwin's brother.
Annie Elizabeth 33 married, married to Edwin Siddall, with children - H. (b 1897) (Harry in the 1911 Census but Henry in the 1906 Census) Charles (I don't know where he fits in -- he's not on the 1906 or 1911 Census) Master E (I'm assuming Edwin or Edward -- Edward is on the 1906 and 1911 Census -- but Edwin Siddall was born in 1900 in Oldham and an Edwin Siddall died in Southern Sakatchewan in 1912 being 12 years.) Miss E age 2 could be Nellie (on the 1906 and 1911 Census) Thomas doesn't appear on the ship list, but is listed in the 1906 and 1911 Census as born in England. Would have been an infant.
The 1916 census seems to have mistakes as well. The Edwin Siddall family is nowhere to be found as of yet. Yet, Annie is given as John's wife instead of Ellen. (John and Ellen's daughter, Elsie is my husband's grandmother.) Both families settled in southern Saskatchewan, near the towns of Weyburn and Estevan.
I have found some evidence in another ship record that Edwin Siddall returned to England in 1952 at age 75 with the last residence given as Canada, destination Oldham, Lancashire, so I assume he lived in Canada permanently. I have not done any extensive searching on the Edwin Siddall family - only as it relates to John William.
Hope this answers some of your questions and that I haven't bored you with too many details.