I found the famly on the 1930 census and it appears that Joyce was born in 1926. (Do you have this census?)
Also in the household was Boyd Hartman, Anna's father, along with Clinton and Carter.Clinton died in Lane County in 1984 and his wife was named Celeste. You may be able to track Joyce through that line of the family.
Do you know who Joyce and/or Joanne married? I found a Joyce E. Davis who died in 1945 in Coos county, but if Joyce had married that would not be her.
Let me know if you have any other info and if I can help.