Today is the panel for Paramount! It starts at 10AM PST/1PM EST/6 PM UK time. While we obviously can't stream it live or see the contents at the same time (there is decent chance we won't see the trailer the same day), assuming the Sonic movie does in fact show up at Cinemacon (which would be odd if it didn't) we will be able to learn the following things.
First, an actor/actress for Tails. Even if there isn't a formal cast announcement, usually audience members can describe if the voice was the same as the first movie or different.
Soon after the trailer is released, we should at the minimum get reports of what showed up in the trailer as with what happened in 2019, with decently specific detail.
I think there are live tweets as things go on where some insiders share what is currently being shown. Not sure if there is one good source for that though.