Hi Joan, I was back at the library today and I had a few spare minutes to look up William's death reg. It lists that he lived in the municipality where he died (Vancouver) for 50yrs, in the province for 50yrs and in Canada for 55yrs. So it looks like they arrived in 1912 - between the census and James' birth as you thought.
His date of birth was 9 Dec 1883 in Glasgow, occupation Retired Accountant, worked in this occupation his whole life, wife's name Margaret Duncan, father James Forrest, mother Elizabeth Simpson, both born in Scotland. His son James was the informant. William was buried at Valley View Cemetery in Newton (in Surrey, an outer suburb of Vancouver) on 14 April 1967. He died of pulmonary edema.
I checked findmypast but I couldn't find any obvious matches for them in 1912. Maybe someone will have better luck on the ancestry passenger lists.
Lynwen