On the VX side early August 2012 DOH is the plug CA. I don’t know about lineholder, that changes every month with increase/decrease in flying hours and pilot leaves. For the remainder of the year the new 48 upgrades are all on Boeing’s. I think last time their most junior CA plug was a May 2013 hire. Lots of SEA FO bypassers.
The wild card is the SLI. Regardless if you’re hired now you’d be about 3,000 with only ~625 retirements in the next 10 yrs. You will be a FO longer than any of the other big 6 carriers.