@Fine_Distinction
I think that going for cuirs against Hannibal sounds like a sensible move even though he is friendly. He is close by so the attack can come sooner and it's easier to reinforce and defend. And if you conquer him you then have one flank totally safe when turning your attention to the other AIs.
As far as I have understod it, not a single AI starts to plot at friendly, only at pleased. (Although Cathy can be bribed against you by some other AI even if he is friendly).
Getting MilTrad from liberalism is the standard play.
Self tech nationalism, bulb education and if you can manage to get compass and metalcasting in a trade, you should be able to bulb liberalism too if you avoid machinery.
There are basically two ways to get cuirs, either you build HAs or war elephants and then upgrade them to cuirs, or you whip cuirs straight. Which approach that is best depends from game to game, but most often HAs->Upgrade is the best.
I'm a sucker for stables and like to have at least two of them, but the key thing is to get a bunch of HAs/Cuirs with combat2 straight out of the gates, so having vassalage or theocracy can substitute stables.
If you take the upgrading path, it's nice to get out a few great marchants to run trade missions to get alot of cash (this is a reason why upgrading is good, because you can turn GPeoplePoints->Cash->Hammers via upgrade.
In either case, once you have libbed MilTrad, you start to tech gunpowder but you don't finish it until you have gold and HAs synced up.
Set a target and work toward it.
Example:
"Hmm... for this war I think I need 25 cuirs, that means I need to build 25 HAs and get 25*170= 4250 gold.. That second GMerchant will spawn at turn X and will reach the temple of aretmetis city turn Y, so then I better start builing those HAs at turn Z at the latest so I have those 25 HAs ready... Better built 30-35 of them, I can upgrade a few more using gold from a 0% slider and conquest gold after I start rolling."
Regarding at what date/turn you get them.. That doesn't matter that much really. If you can hit the AIs before they get engineering thats really sweet because pikes can be abit annoying.
But really, if you don't hold back too much, and if you get enough units you will have a fun time rolling over the AIs all the way until they get rifling.