As I understand it.
F class seats are available for upgrade via Elite status in advance (the old ELTC/ELTS) 3 days in advance for Platinums, 2 days in advance for Golds, 1 day in advance for Silvers, and same day for Platinum or Gold companions. The are also available for upgrade via FF miles anytime in advance.
When they are full, only A seats are left.
A seats (revenue seats) are available for sale at first class price, are authorized for immediate upgrade to an elite if a coach fare in Y or H was purchased, or are available and assigned to Elite members who asked at the airport day of flight and were put on a waiting/standby list.
To answer your specific issues:
I'm not sure but I believe that the standby list is compiled and cleared by time of arrival/request at the airport (regardless of elite status - so the Silver arriving 4 hours prior to the flight is ahead on the list of the Platinum arriving 1 hour before).
The space available upgrades are for F class only. If the F is gone, you can not use the coupon for A, and only Elites get onto the waiting list.
The "first on the waiting list" sounds like a lie. They have you first on a list of requested rewards, but that is only if someone else cancels a reward or upgrade in advance. It does not get you on to the airport waiting list first, you have to show-up for that. Also, those A seats go fast a few days befor the flight to elites purchasing full fare tickets.
You'd best call CO customer care and complain loudly that you were decieved into spending the 10K miles under the promise the upgrade would be available, and now you were lied to about the airport waiting list. Either they will give it to you if you complain loudly enough (use the "my wife is now destroyed about not being able to sit next to me during the flight" line - I know it's sexist, but it often works), or they won't...a 50-50 thing.
You could also offer to pay the difference between your fare and full H class on the leg where F is unavailable, which would entitle you to a immediate upgrade to A.
Customer care is 1-888-WECARE2.
OMNI: notice how I didn't say "look for this in an earlier thread".