Well considering Kira and his friends were on Orb to begin with, they will probably at least make appearences, because that's where they are living (or at least that's what I'm assuming, it's a strong possibility considering that's where they were originally from).

I wonder who will pilot the gundam on top, the color style of that gundam tends to go to the main character of gundam series, so if Athrun is the main character would he pilot it? Even though he had a fascination with reddish type gundams that transformed into planes in the previous series?