3. In case my partner is in the same selection procedure, can both of us be employed in the same country or in the same city?

There is nothing against this, but in reality there is very little chance of achieving this. It is unlikely that you can simultaneously be selected for a suited job to both profiles in the same place of assignment.

However, each of you can apply while indicating whom to put first in case both of you would be shortlisted for jobs in different places of assignment.