I fiddled a bit with the Calculator, and it seems like it is possible to obtain the same results with Kerannii as with Esmera in an optimized run, but it's harder. And post-Eustrin Final, siding with Kerannii will result in a net advantage of +2 Ivalan Acceptance, with everything else equal.
For context, my run has me get to Gawnfall with Lustlord Statues but not Temples, Givini Tunnels, Succubus Band Tour, Ivalan Bank, Sanitation Mages and 50k ProN given to the Order of Silence during the Summit, 40 Religion (with Goddess of Magic statues). And it seems like all of them are actually necessary if you want to ace all votes aside from the two Succubus motions and Ardford Ban, which you don't need. Yes, even the Tunnels. Without the +1 Hester score they give you post-succubi vote, you won't have enough Hester score to get the best result on the Fucklord motion without investing more Sarai influence than you can afford, so it's EXTREMELY tight.
By contrast, with Esmera you can easily ace the council without the Tunnels at all. For now, if you have a fully optimized run Kerannii seems better, but by a hair. And of course, we don't know if the other High Priestess scores will come into play in the future like Annah's did. If that's the case for Hester, Esmera is superior because siding with Kerannii requires you to tank your Hester score to get the succubi accepted, unless you want to get light reforms passed - which in turn will tank your Yelarel score badly enough that you won't be able to get the best result on the Mother's Guard petition, which means no pin and no free access to the Potion Hermit, which might be very important in the future.