I just tried to play a FFA with 5 other hard AIs and I just found it impossible to win, this is mainly because all the AIs with which you don't have a Non-Aggression have you as a priority to kill. It does not seem like a FFA but rather like all against the human. The first such FFA I tried to play was a disaster. I had all 5 players simply assaulting me together in cooperation.
In the next game I tried my darnedest to make as much alliances as possible. At the start when you can increase their favour towards you mostly with resources, all seemed to go ok. However this is generally not enough to get a non-aggression going so you need to do more tasks for them. The tasks that they give you however are just insane. They always ask you to destroy fortifications and buildings which means you have to overextend to achieve anything. And even if you do manage to ally with one or two, they just love asking you to attack your new ally for more rating, or you simply end up losing rating from them.
At some point I had managed to get a non-aggression with 3 AIs which gave me some valuable breathing space, as the other 2 had already banded together and were sending huge waves against me, while I had no one backing me. So I had to concentrate all my resources for defending one chokepoint. All the three of my allies were constantly giving me quests to attack either my other allies or destroy fortifications from the two others (impossible). Eventually, as I couldn't do any more quests, one of them broke the non-aggresion and attacked me from behind. There was little I could do at that point, especially after the other 2 attacked me with a huge fleet (about 3 times the size of my defenses+fleet) and it was game over after a majestic battle .
The AIs seem especially annoying as they seem perfectly capable of making alliances among themselves without any difficulty.
So my question is, how do you deal with this? is there any point in playing with many hard AIs FFA as they'll just all gang-up on you? What kind of strategies do you have to keep alliances? Is there a way to gain favour without doing quests? I tried bribing them but it didn't do squat.
PS: I was playing Vasari.