In the AMGA it states that in exceptional cases subcontracts are possible between beneficiaries and affiliates. Does this also apply to linked third parties (no affiliate, but legal link)?

The Grant Agreement does not exclude the possibility that a contract or subcontract is awarded to a third party with a legal link to a beneficiary (which is not an affiliate). However, the selection of the (sub-)contractor must not be influenced by a conflict of interest. See the examples in article 35 of the Annotated Grant Agreement for further information.Chuck Taylor All Star