I made peace with all three as we don't have any troops to fight - and even a single archer would pose a serious threat, at least to our land improvements. Lost all but one scout to barbs, some crappy RNG-rolls, hope we get better ones when things get in motion, then.
I built our second city, Antium, 1 NW of the suggested spot to leave more space for a gem-city in-between as well as claiming another floodplains.
Here a picture:
Our capital:
A possible settling site, claiming horses, stone and possibly elephants (but no bonus food), at least if we can manage to fight Karakorums culture. Cyrus has a settler in the north on a very nice city site

Maybe we should open borders to him or hatty to get a friend and maybe a religion.
In between we have two possibilities to settle. On top of the gems, giving us pigs as well as corn - but leaving only 1 of the 5 bonus commerce.
The other possible location is 1NW of the gems, still a harbor city, gets pigs and a plains hill. I'd tend to settle on gems nontheless as bonus food is a quite good production source, given slavery.
I decided to go writing directly after wheel to get a possible library + scientist up and running, with our land and game targets we should go for a SE. This way we can lightbulb Philosophy later on. Still not sure if it would have been smarter to take pottery before it.
The map has very few strangling possibilities, i'd suggest we expand like mad and build some army on top, start to harass nearby civs and deny them expansion while claiming the space ourselves. I think Genghis and Huayana are good targets for this, given they are neighbours. We need to keep them small until we get feudalism.
As we have marble we should consider oracle in antium - i don't know if we can still get it given our current research and industrious luis nearby. Oracl-ing monarchy or alphabet would be a good step towards feudalism. Great Library is to be considered, too.
Let's go building happy and fight some defensive wars, going settler grabbing.