GF: Is it possible for the researcher to be employed by the beneficiary and partner organisation in TC?

According to the Guide for Applicants the beneficiary is the host organisation which has to recruit, supervise and provide training for the researcher, taking complete responsibility for executing the proposed action. Partner organisations do not employ the researchers within the action.
For more details on the recruitment process by the beneficiary see please Art. 6.2 of the H2020 MODEL GRANT AGREEMENT for MSC-IF— MONO.
For a Global Fellowship concerning the payment of the fellow's salary, it is admitted that it could be paid by the partner organisation in the third country for the period where it hosts the fellow. In such case, the beneficiary should ensure that the reimbursement rates to the eligible costs as stipulated in the H2020 MGA MSC-IF— MONO are respected and must retain evidence of this. Any Audit carried out by the Agency or the Commission would be at the level of the beneficiary, which has to keep appropriate records (see Art. 18.1 of the H2020 MGA MSC-IF— MONO)