The brass helmet is shown in a painting by Genaert dated 1806, described as a model that was not adopted here is a link to the Dutch Nationaal Militair Museum:
https://www.nmm.nl/zoeken-in-de-collectie/detail/327587/

and another showing the uniform from the back:
https://www.nmm.nl/zoeken-in-de-collectie/detail/327873/

The cuirass was worn by the Garde Kurassiers, as shown on the following links:
https://www.nmm.nl/zoeken-in-de-collectie/detail/265378/
https://www.nmm.nl/zoeken-in-de-collectie/detail/268116/

The museum has an excellent searchable archive, which can be accessed through
https://www.nmm.nl/zoeken-in-de-collectie/