Thank you for posting your list.
Here are my comments.
1/ Luke Thomas Tallott born 1847, Oxon. Awaiting confirmation from Birth Cert that he is indeed their son.

2/ Walter William Tallott born 1849, Oxon. & 3/ Harriet Ann Tallott born 1852, Oxon. Agree

4/ Dorothy Tallott born1855. Unable to confirm this one. No record of birth in Oxen, and wasn't on the 'Jessie Munn' passenger list or 'Oscar' passenger list.

5/ Annie Tallott born 1859, Melbourne, Australia. & 6/ Louise Tallott born 1861, Melbourne, Australia. Agree

7/ Cecilia Tallott born 1861, Melbourne. Cannot confirm this one. No birth record in Australia. Not on the 'Oscar' passenger list.

8/ Edwin Tallott born 1863, Canterbury, New Zealand, & 9/ Henry Tallott born 1866, Canterbury, New Zealand. Agree

10/ Alice Elizabeth Tallott born 1868, Canterbury, New Zealand. This is the daughter I had missing, I found her in the NZSG Certificates Collection, Reference: CTF01868. Alice Tallott married 9 June 1890, Christchurch CBY NZ.

11/ Sidney Ernest Tallott born 1872, Christchurch, New Zealand. Agree

This confirms there were 4 sons & 4 daughters as in Thomas's obituary.
I attache a scan of a handwritten note written at the time of Thomas's death, you will see in the left margin it confirms there were 4 sons & 4 daughters as in his obituary. Also mentions the property at Cust which was 40 acres and then expanded to 140 acres by his son Henry.
If there were a Dorothy & Cecelia, maybe they were adopted? It is strange in the 110 years or more that have past, they are now thought of as his children.
Cheers,
Sunny