PF: In some countries there is no doctoral thesis defence. Instead, the candidate submits their thesis with the signatures of all committee members and then graduates. An official letter from the department can be requested to testify that the applicant will have their degree in hand by a certain date. Is this something that an applicant can provide instead of a defence document?

Тhe requirement is that the applicant has completed their PhD before the call deadline. In case the award of the PhD has not taken place, then the date of the successful defence of the thesis would be sufficient.  In any case, REA can assume that if a document from a committee within the university can prove that the PhD is completed and there is no further pending requirement from the applicant, it would be sufficient.