I am only a few years off but just found this. It could be the William Hallam you have was married to Mabel Vella Trees. William Earl Hallam is the great grandfather of my daughter Linda. Her grandfather was William Evans Hallam Sr. Her father is William Evans Hallam jr. (whereabouts unknown) Have information on WE Hallam sr. if you need it.
I just copied what you wrote to put with Linda's things.
Have a great day! Kari