Are they listed on an exchange? If so they have investors they have to keep happy and debt to the tune of £5b that has to be serviced is not what investors want to hear.
Chairmen or owners can remove money from the club in the form of a "management fee" at regular intervals. I'm not saying they wouldn't pursue more growth and revenue first but ultimately that debt has to be paid off and the other owners of INEOS won't be happy about their money being used to pay debt on a football team.
Not sure mate, they are a private limited company. They may have investors.
And yes they could take fees and dividends etc. But you'd have to imagine anything they could take out of United wouldn't touch the sides of the yearly payments of a £5 billion pound debt.
If Ineos take on debt to buy a company with a view to growing the company as an asset. It wouldn't make much sense to cripple it with debt it couldn't hope to service. Yes the Glazers did it but for a much smaller amount that United sadly could afford to service.
Having said all of this it's probably a moot point at this stage. I don't think Ratcliffe will be taking over.