IF / PF : In the frame of European Fellowships, is it possible to have secondments to TC?

Secondments are possibly only within the EU/AC. Short visits are possible to any country in the world. This applies to the H2020 individual fellowships. For the HorizonEurope postdoctoral fellowships, check the respective guides for applicants for each call, but in principle secondments are possible everywhere in the world. 

IF / PF: Am I eligible for the family allowance if my partner or I are expecting a child at the point of time of the deadline?

IF: The familiy allowance will be paid in case of having 'Dependent children who are actually being maintained by the researcher' at the day of the deadline, without a change of status during the duration of the fellowship. Being pregnant does not qualify you e.g. for child benefit and other services, and thus it doesn't make a researcher eligible for the family allowance.

PF: Changes in family status during the project will be taken into account. For details, see the guidelines for each call respectively clarify matters with the project officer.