I'm sure there will be a new trailer showing the animamates for the first part at least... Remember they are the only characters we haven't seen yet and the first movie is just releasing in 2 months + some days from this sunday when the Anime Expo happens. We haven't also seen Mars/Venus in sailor form yet and they appear and die in Part 1.
I read on twitter they will have a big stand promoting Cosmos so it must have new material. In fact Anime Expo is basically used for companies to show/announce new material or shows. We have just seen stuff for Part 1, nothing from Part 2. I still think we won't bee seeing nothing from Part 2 until May/June ( movie releases June 30th ). At least that's how they did it with Eternal. Trailer for Part 2 was just one month before the Part 2 japanese release.