With each island surrounded by ocean tiles, will that delay resource trading until Astronomy? Or does border-encompassed ocean count as coast, in trade route terms?
It will not block all the way until Astronomy I think. It may be possible that each team will have to settle a city on the "mainland" though. In other words we may not have resource/trade connection right now, but when we settle Resonance and they settle somewhere else on their coast somewhere, then we would be connected. We won't be able to scout out their land up to their capital otherwise due to ocean and it's the same for them scouting us though.
In other news, if we're reaching a consensus on some long term diplo-related things I definitely want to be on the lookout and censor anything that would ever make us seem hostile to Vikings right now - seems like we might be wanting to keep them as friends. So yeah, we can't exactly say anything to outright discourage them from "settling towards us." It's more on in-game actions and situations that pan-out. For instance if we get that peninsula and garrison it just well enough, and fully settle out the Resonance/Cosmos/etc... plan that just means we've claimed the territory on our side at least, kind of an unspoken thing.
Again, I don't think it's actually possible to even stop them from settling a couple cities on their own side of that "petal" especially if mountain ranges on in the middle, so we just wouldn't try to.
But ultimately is does matter how they are feeling and how well we need to work with them to keep them from attacking us, I agree. If the team on the other side of them just treats them poorly, it could be easy; on the other hand CDZ may decide to be bloodthirsty against everyone and it could be hard. But keeping up a firm idea of our tech situation and possibly some other things promoting alliance, like a mutual set of resource trades, could work.
I'll work on drafting up a message that we can probably send this next turn, and for that matter anyone who has some ideas on waiting for the Mavericks can also be ready.