Pastimes has been advertising more Magic event for Gen Con, primarily a Championship series of tournaments. When will these be added to the event listing?
They'll be added when they get added. Gen Con typically processes the events in the order they received them.
How do I find out who will be signing Magic cards?
If you want any company to run events at Gen Con, you are more than welcome to contact that company directly and ask them to submit events; we are not able to force anyone to submit events.
Gen Con LLC