1. homedirectory created for each user normally will have the same username as the directory under the searc_path. Share the search_path and extract the directory names and cross check randomly the directory name with the username in the permissions tab on the folder.
2. drive mapping has to be done from the AD. Storage can only facilitate the homedirectory space. In the migration scenario, if you can keep the new storage name (\\cifsservername) same as the old name, then you can avoid doing the re-mappings.