Managing Director of a Private Limited Company

Salini ,
pvt. limited companies are not required to file mgt 14 for the purpose mentioned in Sec 179(3) and rule 8 of the companies act 2013.

Yes An individual can be a managing director of two companies, but an individual cannot be a whole-time director of more than one company.

No need to file spl resolution in form mgt14 as it is exempted from pvt Ltd companies as per rule 8 and section 179 (3) of cos act 13.

There is no concept of MD/WTD in private companies and Schedule V + 197 is not applicable so MR -1 is not required and not any approval of Shareholders for payment of remuneration and with just board resolution you can change designation ,but it's recommended to file DIR -12 &MGT -14 for Board resolution.

MD or Whole Time director can become MD/WTD only in subsy u/s 203(3)