If an STC holder determines that its modification does not affect FCBS (or create new FCS), there is no action per your presentation. Is there any data that is needed to be presented to EASA to obtain EASA's approval for the no action determination?
No. Subsequently, during an audit or if an operator or NAA identified one issue, something could come up and EASA would take action.
According to the EU regulation framework, design approval holders are responsible for the conduction of such evaluations.. Non-EU STCH located in the US should already hold compliant data for ageing aircraft regulation because of their compliance with CFR 14 under section 26.47. EASA can rely to a certain extent on these data and on a design approval holders to make their assessment correctly. However, STCHs should be conservative if they're not sure about the affect of an STC on FCBS.