I really enjoyed your post
I keep thinking that unfortunately they are going to have to mention the quarter quell, but maybe to 'get away with it', you could have Snow announce the 75th Games is a special event, but then don't have the line about previous victors going in. Then you could just have jungle shots of the arena and the beach, maybe passing shots of tributes in training but you don't see their faces? Although that's not really overly exciting either.
I'm expecting that we will see some element of rebellion though, maybe while Katniss and Peeta are on their victory tour we see the crowds pushing back and maybe even the gun shot going off in D11? But that goes back to your first idea of using President Snow which I do like, he was established as the villain at the end of THG so even non-book readers would realise the threat he poses. Perhaps you could have a trailer much like THG finished off, you see President Snow first watching footage of them again and then rocking up at Katniss' house.
Loved your last teaser idea about drunk Katniss, it's one of my favourite scenes and I desperately hope it makes it to the movie. I think the teaser might be more book fan based, that would be pretty awesome.