A quick update for anyone working similar searches.
I've been watching Alaska saver inventory on DTW-SEA. This morning F appeared on Friday 6/30. I jumped over to my reservation and modified the SEA-YVR flight to DTW-YVR. I kept the original SEA-YVR flight in there so will overnight in SEA. Only additional cost was $5.60 for the extra TSA fee so I am now in F/J the entire way to SYD.
I'm still watching SFO-DTW on UA. I'm not as hopeful being that there is only one daily nonstop and I'm guessing Monday mornings are not prime saver inventory targets.