Here are my notes from the "Star Wars: Rebels" panel at NYCC yesterday:
1 ) Cartoon is about a year away from airing.
2 ) Will initially air as a 1 hour special on the Disney Channel.
3 ) Series will premier a few weeks later as a half hour series on DisneyXD.
4 ) Simon Kinsberg, who is a consultant on Episode VII and working on one of the spin-off films is working on the series.
5 ) Animation is starting now, Dave Filoni is in Asia right now getting the animation team started.
6 ) Voice-over work is currently underway.
7 ) The series art department went to the Lucasfilm Archives to look at the Ralph McQuarrie original art to see not only the designs, but the brushwork, colors, weight and shading.
8 ) Design team utilizing vast amounts of unused McQuarrie concepts for settings, ships, props, alien species, etc. for the cartoon.
9 ) Series takes place 14 years after "Revenge Of The Sith" placing it 5 years prior to "A New Hope".
10 ) After the turmoil of the Clone Wars, the Galaxy considers the Empire a great stability.
11 ) The Empire moves out into "The Frontier" (possibly another name for the Outer Rim?) to take control of the multitude of "independent systems".
12) The Empire does not have the manpower to just waltz in and place planets under their direct control yet so they will manipulate the planets' governments into either joining willingly or replacing their current leaders with ones that will be more friendly to the idea of Imperial rule.
13 ) Main setting for series is the planet "Lothol" (unsure of actual spelling), an independant world that is rich in minerals but too poor properly exploit their mineral wealth.
14 ) As per George Lucas himself, Imperial era troops (Stormtroopers, TIE Pilots, Scout Troupers, et.) are NOT clones but conscripted and volunteer soldiers. The clones age at twice the rate of a standard human and were put out of production at the end of the Clone Wars so there are none still in fighting shape. Those clones that did not die yet are either retired or used to train the enlisted Stormtroopers.
15 ) Imperial E-11 blasters in "Rebels" will have the Vintage Kenner weapon's signature flaring on the barrel.
16 ) New Imperial Trooper being introduced- the AT-DP (All Terrain Defense Pod) Pilots. Look to be a mixture of AT-ST Driver, classic Stormtrooper and AT-AT Commander.
17 ) AT-DP is based on unused McQuarrie At-St design from "Empire". The original McQuarrie design actually appeared in the old "Star Wars" newspaper strip drawn by Al Williamson back in the early 80's so there is already precidence for this design being somewhat canon. This is a 2 person walker in which the gunner sits in front of and below the pilot like in modern military helicopter gunships.
18 ) Kenner Imperial Transporter to appear in series in a slightly modified form. It is larger, more heavily armored and armed with additional turrets in the front.
19 ) Kenner TIE Fighter to be main Imperial starfighter in series.
20 ) McQuarrie concept art IG-88 may appear in series in some form (image very briefly glimpsed in behind the scenes video during panel).
21 ) Imperial propaganda posters will be prominant part of series scenery.
22 ) Heroes will be underdogs like in EP IV.
23 ) Heroes will not have established well stocked supply chains and will have to either repair, or find a way to replace (i.e. probably steal) any assets they lose during their struggle.
24 ) All ships are being designed and 3d rendered in actual scale to one another unlike physical models which are usually scaled all over the place depending on what shots they are being built for.
25 ) The Galactic Senate is still in session, although the Emperor holds all of the real power and they are more or less puppets under his control (Senate is abolished just prior to the events of EP IV).