Good luck to you on this. I do think before you set out there are a few things you might want to clear up:
1280 x 720 background of an auditorium with a stage, ample standing room and a large main screen behind the stage.
Did you check out the asset pack I provided with last year's build? We have a 1280x960 version of the existing background.
Some good reasons why it's scaled down are:
1. For consistency with the characters, since most of them are low-resolution. I'm not sure you gain much by running in 1280x720 when most of the characters are 320x200.
2. For performance. Because of engine limitations, you have to run the awards client with DirectDraw (i.e. in software), and it may run slow if you display lots of sprites in high resolution. This is something you should definitely test properly before switching to higher res.
You argued in the other thread that higher resolution would make it less crowded in the audience. That's not automatically true: It depends solely on the size of the characters relative to the resolution. To get more space, you'll have to draw a background where the characters are smaller. With the dimensions you propose (100 px height in 1280x720 resolution), that will be the case – they'll be about 88% the height of Ben Jordan in the current version, but of course the tradeoff is that everything looks smaller/farther away, as in this mockup (Nelly and Ben are both ~100px tall):
Whether this is preferable is debatable. Personally I think the people on stage become a bit remote, though it's not too bad. However, if we need much more space in audience, I would instead suggest making the background scrolling (left-right). I feel like the wider aspect ratio shown here isn't ideal, given that part of the height is taken up by the chat window; I think scrolling would make more sense.
Switching to higher resolution also means you'll have to replace every graphics resource (buttons/UI, titles, some of the fonts...), redo the intro screen, and probably fix the code in a number of places. Oh, and since AGS limits character scaling to 200% max, you'll have to upscale low-resolution characters outside of AGS and reimport them. All in all, it's a significant effort.
Oh, and another important point! The client runs in a special build of AGS 3.3.3: it requires late_repeatedly_execute_always(), which has only been included in the latest 3.3.5 build – AFAIK not in any 3.4 build. I don't believe 3.3 supports 1280x720 as a resolution; the closest is 1280x768.
On a personal note, I quite like the current background and the traditional look of the ceremony hall, like an historic theater, and I think it would be a shame if a new background lost that classy charm.
Music is needed for the gathering before the show, or when the host spills their drink. Anyone is free to contribute music in any style they wish, but I would prefer to use a handful of tracks all in the same style. My wish list is 3 or more muzak (relaxing, instrumental) tracks with melodies inspired by great adventure games.
We do already have a number of music tracks for these bits, but sure, could always use more.
SpritesWe will probably re-use all of last year's sprites, but it would be good to add a few new ones. A full walk cycle of your sprite is needed with four directions. Character height should be close to 100px.
Because of work I did last year, characters can be any size (though in practice I pre-downscaled very large ones to improve performance), and will be scaled appropriately in-game. It's not feasible in practice to require all provided characters to be the same size.
Oh, and I think I know what you were talking about with trophies. There was one in the offline game version of the ceremony, but it's never been used in the online client (partly, I think, since the graphic style doesn't quite fit):
If someone creates new trophy sprites, it shouldn't be too hard to somehow integrate them into the ceremony.
As a piece of general advice, if you haven't already I'd highly recommend starting out by familiarizing yourself with the code and testing that you can compile and run it, and actually host/guest over IRC.