Hi,

Oscar W. Pearson
Died: 29 April 1947, marion Co. per death cert #2838
Source: Oregon Death Index 1898-2008

Can't tell from this information whether or not he was your Oscar.

There are two people who are willing to look up obituaries in this county at www.gengathering.com. You do need to create a user ID and password to enter the web site but access to the volunteer info IS free.

The 1940 Census is the most recent one available. For additional info about Mabel, Wallace and Ronald, you'd have to find their death info. Let's start with Oscar's obituary and see what other info it has. Successful Searching!
Go to http://freepages.genealogy.root