Ljubljana had a three point drop from T61 to T62. He appears to have founded at least one city within 10 turns of that. Would need to go back through the saves to check.
Cities can be gifted once, within one turn of conquest IIRC.
Regarding plans, I think at a minimum you should have ancient walls at Allan McGregor and something like a sword or horseman (ie 36+ CS) in Borna Barasic for defense. If we can find Machinery (and you can complete it) and upgrade one archer to a crossbow that helps your defense against retribution - your cities' ranged attacks would be at the crossbow CS.
My plan is to have four jongs, two swordsmen, two chariots and a battering ram (just in case) make the initial attack. It's a small force but that should work - jongs at CS 60 vs. city defenses will make quick work of things. The timing works out something like this:
- Mercenaries completes T94
- Upgrade navy & warriors on T94 & 95 (710

for the navy + 55 or 110

for the warriors depending on if I pull the sword off Big Island)
- Sail for the channel west of Borna Barasic with the above plus a galley. It's five turns to reach the small island between BB and Wodin with one turn of "slop" to maneuver. Call it Turn 101 to be in position to allow one turn for maneuvering - can't go in ocean tiles, after all.
- Declare and attack on my turn. If he doesn't have walls up three jongs and an amphbious swordsman should be sufficient to take the city. Walls might take another turn to knock down.
I think the best way to do this would be to cede Wodin to China as soon as I take it. In that case you'd want to be following with two Classical land units (horse/sword) and perhaps an archer or crossbow. You would want to have a governor available because there will be loyalty issues. If there isn't one available then I'd keep the city, move Reyna over and then your land troops would defend from ground attack while I move onto the next one and hopefully relieve some loyalty pressure.
Woden's got four cities that he's founded, plus two city-states. I have to assume that he and Phoenicia are tied up with the happenings at England/Japan. He has not been building districts - only Frigga has a Holy Site and there appears to be a placed district (Campus?) 2SE of his capital. Ljubljana, likewise, has only built Cothons and Aqueducts. I have to wonder how much of their milpower is land units. His 28 CS for (W)odin is 25 from longships and 3 from the palace. He's got nothing better than warriors for melee/anticav. They may have taken a gamble that they could use biremes and longships to wipe someone out early and piggy back off their opponent's development. They may have also been counting on Mercenaries not being "easy" to get to.
Beyond the initial four jongs getting additional ships out will be slow going. They have a construction cost of 300

(so a

cost of 600) though by the time they unlock I should be able to faith purchase one every ten turns. The +100% bonus for jongs isn't available until I complete Exploration so I'm not counting on building any. Another option would be for me to hold Mercenaries for the additional time it will take to build two more quadriremes as spares. I'm currently completing quads on T83, T88 and T93. I could get out one more on T98 and another on T103 if we wanted to wait. I could hold Mercenaries to T98 and I shuffle everyone down the coast to Borna for jong upgrades there. However, you'd need to get another coast tile to speed that process up so I can upgrade two ships per turn.
One thing to perhaps get done sooner rather than later, if you think it'll be fine to do so, is to embark the warrior at Borna Barasic and defog the area immediately southeast of the island. That'll tell us how wide the channel is and whether or not Woden is maintaining any pickets in the area. If he is then I'd either have to take it out OR sail past it and declare once I'm by it.
Thoughts?