This is a very fiddly mission. Sorry Gweilo but I really didn't enjoy this one but that is probably more a reflection of my ineptitude!
At the save point only 2 out of 4 Allies and 0 Cities ruled so I was expecting to have to replay this again - but the minions sent out to plead for alliances and the army sent out to conquer all magically achieved their aims seconds before time ran out. Somehow, success was achieved!
In terms of city design, not too different to M1 apart from groundwork set up for Elite housing areas for M3/4 and the warehouse mess from M1 partially resolved.
Yes, this mission requires you stay on your toes diplomatically to react to the changing situation on the empire map before the time limit expires.
It was fiddly for me too; during design I tried and tried to find a way to allow you to conquer a city and hold it reliably without it rebelling with only 1 military unit. I couldn't get that to work and that's why you see the palace introduced (earlier than I wanted) to allow the second military unit.
As I told user3 in his comments, I tried some experiments in this campaign design, and hindsight now shows some of them were not entirely successful in the 'fun factor' department.