I think this is correct
Eileen Chazalon was Eileen Maud nee Williams at the baptism of her daughter (also Eileen) in Montreal in 1910
see 1911 census, and Drouin Collecton
Eileen Maud born Queenstown, Ireland. (haven't found that birth yet, but name may be different, see below)
father was Adrian Chazalon
in 1921 the two Eileens and a son Eric Ronald born in Turkey
in 1939 the younger Eileen is using one of her other names Cecile and mother has become Ethel M. Born 1882.