1) No, Digital Age comes up as ''coming soon'' when you're in the Space Age. They also mentioned in the stream at least 2 ages in the works.
2) There never was any friendly fire in the game where your troops could hurt each other, this won't do it either
4) Factories never gave troop space, their levels unlock more factory troops and upgrades, differentiating themselves from barracks. Barracks again getting expertise, probably to limit hardware stress on people's phones. Then again, donation cap got boosted by 20 through the university research.
5) Interested in a detailed explanation myself, will probably find out once I craft for an event.
6) Result of air capacity increasing by more than 50%
7) The age itself doesn't add much, but the update has changed the dynamics a little bit. AA vs AA and CWA vs CWA seem to be better looking on the offense side since the increased air capacity looks to overshadow the damage buffs given to air defense and SAMs. In Space Age though, defense buildings again get more of a boost than offense units, and there's that library research that gives major boosts to anti air buildings.