You might also look into the details for a 'Lien Sale' or 'Mechanic's Lien'. It varies from state to state. Not sure of the WA requirements. In some states you have to be a shop with an open invoice, in others anyone can do it for 'storage fees'. There is some paper work and hoops do jump thru, but not a 3 year process.
Something like this, (I did it in CA years ago):
DMV gives you the registered owner's last known address and the Lien Sale paperwork.
You send the DMV form via registered/certified mail to the last known address of the registered owner.
They either get it, sign off to release, or say they want it back...
Or - It comes back undeliverable.
If undeliverable, you get a LEO to inspect the VIN and tag numbers, sign off on the DMV form, take all that in to DMV and you can get legal title.
From your description of no plate, it's possible it was never registered for street use, at least by the guy that left it with your friend. That might make things easier or more difficult.