Yeah Asymptote really isn't too bad with the oasis being there, not quite as good as a second clam (and we won't be able to win the culture war fast enough for 2x clam and oasis) but it's not bad.
As for the overall plan - I think we're overestimating the Maverick threat, to things past their own "petal" especially. I could see it being a concern to settle a city - eg. Axiom - actually on the Maverick petal.
But it's a really, really long haul by sea for them to get anywhere else. And remember, with culture from Continuum/Quatron, we can see their ships soon after they round the point. So we'd have something like 6-7 turns headsup anytime they sent ships around that way, before they got to Resonance/Cosmos area.
Once we get Caravels, we could also be practically invincible to sea attack from them. They can't move off the coastline, so we park a couple of Caravels on the coast, massive Strength advantage, and they are done. They're not going to be able to afford 5 triremes and a land army in galleys, it's just not feasible - and that's assuming they focus all on us and not even Sirius. By the time we get Astro I wouldn't consider it out of the picture to blockade their island - triremes are all right against galleys/other triremes, but after that the odds just fall off so sharply.
So in short - my thoughts would be that the Maverick threat isn't that bad - assuming we ARE careful about anything around their petal, I agree.
I am ok with Asymptote though, various reasons make it all right, (AMAZON workboats and available workers is a good reason to start) and it's fundamentally not too different from Cosmos in the short term. So I could see us doing:
Asymptote
Singularity (obviously Singularity needs to be settled by now, fifth city is absolute latest, it's just too valuable to put off)
Cosmos (copper, maybe we're calling this something else now. I am ok with the current "Quantum" site or NW of the copper, either way. If we're settling this later we obviously adjust to developments that happen, if we were settling now or next I'd go with the Quantum spot)
Horizon - this city will take a while longer to really become profitable, before we can afford chops/plantations with worker time, it's just not worth settling quite yet.
And then more mainland/towards India, I could certainly put it off for about that long.