This question has been answered by goldsky. See the first response.
When you run the advanced installation, usually it will take you on a page where you can define the paths, including changing their names
connectors folder MUST be web accessible, so it should be placed alongside with manager, although you can change its name.
you may only move the core folder.
AFAIK, what the rootfolder means is out of the httpdocs or public_html folder, not beyond the domain's folder.
+ ... + core/ + ... + subdomain1/ ++ core/ + subdomain2/ ++ core/ + httpdocs ++ assets ++ connectors/ ++ manager/ ++ ht.access ++ index.php ++ subdomain1/ +++ ... +++ index.php +++ ... ++ subdomain2/ +++ ... +++ index.php +++ ... + httpsdocs + ...