I want to create a main website say,
www.myweb.example which has the main functionality such as admin panels, db's etc.
Then I want to offer clients a customised front-end (change of css and logo) so it integrates with their business and in addition I want the option of the site address being a sub-domain of the main website or a different URL altogether. i.e
The front-ends and main site need to share the same database so that they are synced. The front-ends would only surface data that is relative to the individual client and would need to perform CRUD operation on the database.
Can my requirements be met through a single site or will a front-end need to be developed for every client?