- For the name : effectivly long name is present on the ground : https://www.mapillary.com/app/?pKey=819125039117004  also with "variante like https://www.reflexcity.net/bruxelles/batiments/patrimoine/elements-classes/sites-semi-naturels-classes/vallee-du-vogelzangbeek sometimes with "vallée"  sometimes not , while the legal document for pretected area omit this ; so i think we can keep the long name BUT as mentioned by bxl-forever  that must match the billingual convention : https://wiki.openstreetmap.org/wiki/Multilingual_names#Brussels

Vogelzang should also be concerved as alt_name as it's in use.

For the boundaries : it was perfectly drawed according the document provided by the note author , but effectivly there is something that don't match because user provided a outdated document that was chanceled by the state council ; i reopen the note for this part. 

Have a good day.