Not sure about any of those characters being G.A.
I also enjoy Mr. Waid on Rocketeer. But I wonder if the other titles have had their day. It will be exceedingly difficult for new creative teams to come anywhere near the heights attained by the original Magnus - that was a fine looking comic. And although Solar was a bit limited by the overuse of the same villain, it was very exciting. Well, it was to me.
The real G.A. heroes brought back recently, Cap. Midnight and Skyman, got me excited at first but I quickly cooled as it all became a bit fraught and the creators decided to change the costumes. Really? They should know better. I think that was the final straw and I decided to cancel my standing order. The odd new comic that I fancy, I will download. Saves space and money.
Doctor Spektor was a Gold Key character, I think.