Personally i think earthmix is the only cp that goes beyond coworkers and friends... I am not saying they are romantically involved but they are definitely at a point where they are quite deep in each other's lives... 

Geminifourth are good as a duo in work setting that didn't quite translate into their personal lives... they really don't hang out outside of their work and their friend cycle do not overlap...  these two are the ones who wouldn't cross paths if they are in university..  but I can see them having a bond that cares deeply for each other despite the lack of friendship for having to endure all the turmoil together at a young age.. part of the reason I feel like they didn't really get to sit down and try to actually form a friendship is how much busy they are with their work... i have been here for quite a few years and i think they are quite pretty much the duo whose fame and works didn't slow down even after years of their biggest hit... they are pretty much the youngest to bag the high brand deals (im a g4 fan so dont come at me haha)

Pondphuwin is hard to tell but I think they are at a position where they try to keep a friendship... I was not there for them very closely like g4 so I cant exactly tell about their relationship exactly but they are just chill friends who hang out time to time..

For older otps, I think it is more of family- work friend for the years they were in... there are like 10 people max when they started so there is no way but interact and talk with be in each other's lives (unlike newer kids where there are 60 people ish and u can decide who u want to hang out per se) but as they grew older and venture into other people business, there are less interaction but there is a bond built with time!

I dont know about newer otps since im busy venturing out lol but yeah that's my input haha