Should an investment firm acting as broker and using a matched principal model be subject to position reporting?

In case of provision of services by a CSD in another Member State, Article 23(4) of CSDR requires to inform the “relevant authorities of the [host] Member State”, and Article 24(4) thereof requires that, in case of substantial importance of the activities of a CSD in a host Member State, the “relevant authorities of the home Member State and of the host Member State” shall be involved in the supervision of these activities.
Which authorities should be considered as relevant authorities of the home Member State and of the host Member State?

Does the obligation in Article 62(1) of Commission Delegated Regulation (EU) 2017/565 to report on the overall value of a client’s portfolio depreciating by a 10% threshold on a particular business day apply only to retail clients?

In connection with an investment firm providing investment advice on an independent basis or portfolio management services, what is, with a perspective on Chapter II of the implementing directive,the legal status of a fee, commission or monetary benefit, after it has been received by an investment firm from a third party or a person acting on behalf of a third party as an inducement, and prior to it being transferred in full by the investment firm to the client?

Does Article 24(9) of MiFID II also apply to payments made by investment firms to a third party in relation to the provision of the investment service of investment advice provided on an independent basis or of portfolio management?