Kim Min-jae seems to be closer to neutral.

Regarding factions
As someone who has watched all the national team football YouTube videos, here is what I felt:
1. Kim Min-jae and Son Heung-min actually talk quite often.
2. Hwang In-beom and Hwang Hee-chan hang out with Lee Kang-in.
3. Son Heung-min and Lee Kang-in don't seem to be on good terms.
4. Kim Min-jae is close with the '96 line, Hwang In-beom and Hwang Hee-chan.
5. I haven't seen much interaction between Kim Min-jae and Lee Kang-in.
6. Son Heung-min is close with Lee Jae-sung and Kim Seung-gyu.
I can't be sure what is going on, but looking at the impressions of Lee Jae-sung and Kim Seung-gyu... and looking at Son Heung-min's interactions at his club team...
...
Hmm..
I'm not a Son Heung-min fanboy.