The first campaign took me 9.5h according to the in- game clock but I believe only counts battle time so it should be 10-11h real time.
To get the 100% you have to beat every mission on the map. There is one that’s hidden. Rank and score is irrelevant for 100%.
I’ve had an iPhone for a long time and I’ve never got a person sending me a SMS. All I get are automatic messages about deliveries and stuff. I guess iMessage is more a thing in the USA?