Hello,
Law is completely silent regarding number of meetings. So if there is no business no need to hold any meeting for Remuneration committee and selection committee.
However Audit Committee is concerned with finance function of the company which is continuing one and regularized by section 292A. So I would advise you to hold minimum 2 meetings per year though law is equally silent for Audit committee.
However if there is any change in composition of committees above then it is advisable to hold the meeting of respective committee and take note of the change in composition.
Section 285 has nothing to do in respect of committee meetings.
My personal practice
We used to have at least one meeting of Remuneration committee and selection committee for formal discussion regarding current remuneration structure of the managerial personnels and discuss changes introduced by law during the year.
Last FY we had 4 quarterly Audit committee meetings to discuss and finalize quarter results for our unlisted Public and Private companies. Well this is my personal opinion and practice.
Best Regards