I think that most of these four questions stem up from the lack of clarity in understanding the difference between the actual meanings of the terms " workman" and " contract labor ". For the sake of simplicity of understanding, I would like to avoid the statutory definitions of the terms, very particularly, as they occur in the Industrial Disputes Act,1947 and the Contract Labor (R&A) Act,1970 respectively. Workman refers to the workman directly hired, controlled and paid by the employer himself so as to create a contract of service between them. Contract Labor, on the other hand, refers to the workman engaged by the Principal Employer through a Contractor with whom the PE has entered into a contract for service. Legally, therefore no contractual relationship of any sort between the PE and the Contract Labor though the latter works for him. In this back drop, "No" is the answer to your 2nd and 3rd queries regarding works committee.
Regarding the first question , as far as I know and understand there is no explicit statutory ban on simultaneous dual or multiple membership of trade unions. In case of any dispute between the unions as to the membership of such members, they would be treated as no members of any union. Therefore, no workman in the establishment can have simultaneous membership in more than one union in the establishment.
Regarding the liability for payment of bonus to contract labor, the opinions of the higher judiciary are also divided. However, whatever the contractor's charges quoted, approved and paid include the statutory bonus payable to the contract labor too. Therefore, the PE has to ensure that bonus is paid to the CL by the contractor.
Almost none of the PE gives bonus amt to Conteactor to distribute amongst his employees therefore contractor never gives bonus.
In such situation whose responsibility is to disburse bonus.
Amt of bonus is to be borne by whom ; by PE or by Cont. Pl clarify