Originally Posted by jsloan

1. Yes, that's correct.
2. No. However, if you feel like risking it, the SFO-OGG upgrade process will continue to run between T-24 and ~T-3. So, the longer you delay checking in, the greater the chance that you might both be upgraded together before check-in, which doesn't require a split. However, you run the risk of losing out on preferable E+ seats, both on SFO-OGG and on EWR-SFO.
3. On the way out, you should be immediately after him. If you elect to split the reservation on the way out, it's my experience that on the way back, you'll be at the bottom of the list for Silver members.

What day of week are you flying? What type of aircraft? In general, the chances of an upgrade as a Silver are never good. California to Hawaii used to be a fairly easy upgrade for a Silver, but that's no longer the case. UA has dramatically reduced prices for the first class cabin, which has resulted in many fewer seats available for upgrade. UA will also sell upgrades to passengers during the check-in process, and many people may be tempted on an overwater flight. If your flight is on a 757-200 (with lie-flat seats), your chance of a free upgrade is virtually nil -- people will book those preferentially. On a 737, your chances are small, but 0/16 is obviously a good sign. Your best chances for an upgrade are midweek.

Good luck!