Silly question
Assume Pacific Time?
Yeah.
As for whether they release footage online - it really depends on what they bring. For them to release everything online, whatever they bring has to be fully ready for public consumption, VFX-wise especially, well timed relative to film release, and appropriate amount of content.
So that does rule out ANY JL footage of any sort, a full 2-3 min WW trailer or reel (but a teaser at this stage is good and in fact what I'm expecting - debut it at the panel, release online, then have it theatrically with SS), or any footage looks further ahead. Anything they have for Skwad (say a first clip) they'll drop online for sure probably.
As for WB's other films at the panel - full Fantastic Beasts trailer for sure I think, a new Lego Movie trailer too, possibly a Kong Skull Island teaser, and hopefully a Dunkirk teaser too (apparently they finished putting it together a few days ago)