Disabling/changing "choose one" via configuration for the hippo selection plugin

The use case is that the hippo selection plugin is used to fill a docbase property with a uuid that links to a certain document.

The valuelist that is used is a build up value list of uuids of documents.

The "choose one" ("kies er een") option can be selected and will fill the given property with an empty string (for links, uuid, properties like docbase this should for instance be "cafebabe-cafe-babe-cafe-babecafebabe" instead of an empty string).

1). The main change would be to be able to disable the "choose one" option via configuration in the cms-console.

Other options:
2). The ability to give a default value along with the "choose one" that will be filled in, default is empty string but be able to add for instance "cafebabe".
3). Be able to change the label in configuration of "choose one" (but this has of course this issue with mulitple values for different languages).