For the background: Just tell us which one you like and we will put it in instead. But it's really not that hard to figure out how it works. All you need is nifscope and a programm to view dds files; even i managed it in a few minutes
I always forget about Butuan. Then we do have some kind of situation here. Honestly, i don't really like to see Gajah Mada in the mod.
The good thing about Butuan is that hardly noone knows anything about them. And all i can think of is "indianized kingdom", so we can use any LH from India to Phillipines.
Some examples:
Den's Taxilas
Giving them the old Vikramayaditya and Chalukya is using Chandragupta Maurya instead
Shaybani Khan with another BG
Fernanado Marcos with another BG and reskinned clothes
I'm sure i will end up using one of those in my version, it's up to you to decide about the offical one.
We don't need a second LH for the civs, that's true. I mean, most of them didn't last long enough to have two significant leaders

. SoI doesn't switch LH iirc and they are doing fine.
I was asking because we could use Sejong as Hongwu, they do look alike, and we could use the old Bilge as Bilge again.
Koreans can settle Kyushu, right? It's a nice city with some resources, and a naval base to attack Japan with ships. Korea deserves a name for that spot on the very west of Kyushu: Gilyagaeri. It's the Hanja reading of Yoshinogari, where they found a large Yayoi town, and Yayoi people are pretty likely immigrated from Korea. Okay, it's a little speculative, but it's better than having a city name in Japan that's supposed to be in Korea. Renamed to Yoshinogari if conquered by the Japanese, but not vice versa. The 2 tiles east of it can have that name too.
You just can't have enough of unique city names
And thanks to veBear for the tutorials. Already used it to make Gaozong less chubby than Kublai is.