There's still a lot that's not clear to me like
What happens if mhj isn't asked to resign by the board on 30th April? Can they force her out or is it going to take a court case to force her out?
On similar lines, what if NJ wants to leave hybe? Can mhj end their contract directly or will it require hybe's approval?
Depends on whats written into the contracts and on Korean law.
For example in UK law you have something called drag along rights, which means if the majority owner is selling they can go to court and force the minority owner to also sell their share. In this case, if Hybe wanted to sell its Ador shares to Source, it could force MHJ to sell.
If she isn't asked to resign, or if she is and the board disproves it, Hybe has to keep trying to get her out, potentially (again if Korean law is simular to UK law) with an unfair prejudice claim. Basically saying the company is being run in a way that is unfairly prejudicial to a shareholder or a segment of them.
If NJ want to leave, it depends on their contractual terms and who they signed under. If MHJ really got full control, I think the contracts are under Ador, and if not, its grounds they may be able to claim that Hybe was unfairly able to interfere in a sublabels work despite them being independent (debateable if she has control but lets them go on if she is being a good director to Ador but depends on if Hybe decides to pursue it). Depending on how they swing it, they may be able to get the contracts dismissed. Remember Loona only got out because the income split was really weird, can't remember what happened with EXO but I heard they didn't win and 'resolved their differences' which is code for they paid SM off - so the contracts need something weird in the formation beyond the actual binding to escape, otherwise its down to buying out the contracts. Realistically, if the public sentiment is enough and the damage to the Hybe brand is big enough, the SH may force Hybe to let them go but it would need to get far bigger attention than it currently is, like BBC news level to a point that Hybes major SH's get mad at BSH and with the market cap decline and the bad attention from all of this, that may not take much doing.
But again, they will be weighing up their options, and if the general public opinion is bad enough, they may have no choice but to let them go and so far its not a JYJ situation where they were able to keep some members and retain a highground of fans for said group. If they think the evidence BSH has and the damage is big enough, he may loose his seat. Especially considering all they went through to buy SM only for Kakao to win (including paying LSM waaayyyyyy too much for the shares), grab bubble as a concessions prize and JYP to start making its own platform and move their acts over so basically making it useless. Their only win was to buy shares in an unstable company and get some idols onto their platform but said platform pays the majority of the money to the idols so are peanut profits.