You managed all this in like 103 turns right? Thats impressive in itself!
Any tips?
Depending on how good is the land around you, you may not be able to build HS.
At the attempt I posted, I was too late for HS, so I built oracle to finish liberty tree, used GE to build HS.
In another game, I got HS but missed the oracle.
To achieve this you need to have good land around you. You cannot do this if your capital have just grassland around you. Though Mongols seem to have bias for plain starts, so production is usually not a problem.
Scout-Scout-Granary-Monument-Great Library (Maximize growth. You bottleneck is researching Philosophy-AH-Trapping. Lock growth tiles and switch to production focus on population increases)
Pottery-(AH)-Writing-(AH)-Trapping-Philosophy
On Immortal you may miss great library. When I did a replay I lost GL race on turn 38.
On Deity you won't be able to get great library, so you go for 2 city start. On immortal you can afford to stay at one city until you build NC.
I don't think the detour to plastics pays off, especially when you are hard teching a bunch of stuff... (15k +

impossible to make back before game ends on the basis of RL benefit. Even factoring in hydro plant I think its still not worth it)
Hmmm, wanna try to replay from turn 150 save to see if you can finish faster without going for plastics?
Research Labs give huge boost and you need it a lot, since you have to go back and research bottom combustion path.