Following is what the Help section says:
We don't delete duplicates, we merge them.
Merging ensures that the Activity Feed, Trusted List, and any unique information on the duplicate profile will not be lost. If anyone had a link to the old profile it will automatically be redirected to the new profile. Deletion creates dead-ends in our database and leads to confusion.
http://www.wikitree.com/wiki/Deleting_a_Person_or_Account
If these were partial duplicates of Johanna Welter, could you merge them into her profile?
If there are exceptions to the deletion rule, others will need to address it.