Thanks for the advice everyone.
My main plan was indeed to go Goddess of the Renewal. I strongly considered Goddess of the Hunt as well, since I'd have 6 easy access camps with just 2 cities, but Renewal has strong science bonuses and will scale much better with expansions down in the south. My first expansion was gonna be the city to the northwest actually, it has the potential to be a very good city quickly, and can split Settler production to help settle north/south simultaneously.
God of the Expanse has already been taken so that's not really an option. Protection is an option I hadn't considered, but I think I'm not going to go for it because I want to prioritize my UB and go for defensive settling, so I don't see too much a reason to go down to the lower half of the tree. AI Japan doesn't tend to utilize or even pick Protection very often anyway, so I'm not too concerned about that.
I was debating Progress/Authority, I think I have too much good land and Iroquois bonuses are more expansionist in nature, so I don't really want to go Tradition. I was not actually planning on settling those floodplains to the east, just settling slightly to its northwest/southwest.
I'm surprised Mongolia is considered this dangerous of a threat, there's not a lot of city-states he can viably tribute and he's in the corner of the map, but I may end up having a harder time against Mongolia than I'm anticipating.
Since turn 0 I would go monument stonehenge then looking to buy a worker instead of producing it. Even on Deity Stonehenge is not that difficult to get. Then I would go with renewal / progress then focus on longhouses then on working towards terracotta army. Good defensive cities and good timed wars with your UU would eventually give you an advantage towards the aggressive AIs at the side
This is actually a good strategy I should have considered. Of course it's a bit late to go for Stonehenge now. I went Trapping first because I saw the camps and I figured getting camps out and then picking Hunt would be a strong kickstart to my culture. I've shifted away from Hunt after seeing the land south, but that was my intention beginning the game.
I'm still wondering if an offensive war with Japan is going to be worth it, but I'm leaning towards Progress/defense right now. I'll see how it goes.