I'm not sure how much attention you pay to the boards but you say
""Apparently Walter Maa Louey ( Walter Mar) was the eldest of the nine children siblings and was born 1879""
If you count,,the children I have listed as those of MAA LOUEY and Sarah...total 9!!!
Walter 1879 (mother surname as WATSON)
Charles William 1881
Ada Elizabeth 1883
George 1885 (mother listed as WATSON)
Rowena Viloet 1893
I cannot say why Sarah is listed as WATSON on 2 births BUT I can say it wasn't uncommon for mothers surname to change between various records..Finding her birth/death might help solve that mystery...
Maybe she was illegitimate OR maybe her mother remarried and Sarah used both/either surname????