My experience is that links to pages within the active Sandvox Site Document stay connected if you edit the Page Title in the Inspector or edit the File Name in the Site Outline.

If you delete a page that has been linked to within the Site Document, the link breaks and you are not warned nor is it easy to find the broken link.

The Find/Replace option in the Sandvox Edit menu becomes available only in the HTML editor window i.e. when editing Raw HTML in Sandvox Pro.

Broken links have to be found using another application searching the published site, such as:
[Integrity - website broken link checker]