Yes, this setup is possible. You can map selected custom domains to individual subsites using a domain-mapping solution, while keeping other sites on subdomains. You’ll also need the correct DNS, SSL, and server configuration for each custom domain.
Yes, it’s possible. WordPress doesn’t provide this as a built-in Multisite feature, but a user-switching/impersonation plugin can allow a Network Admin to log in as a specific user without knowing their password.
