Best zoning practice dictates that each zone can only contain a single:

Best zoning practice dictates that each zone should contain only a single initiator (HBA port) for security, stability, and ease of management. This prevents unintended communication between initiators and reduces the blast radius of issues.

An alias is a user-friendly name for a World Wide Name (WWN), not a device type that is restricted to one per zone; multiple aliases can be used within a zone to refer to devices.

A zone often contains multiple targets (storage controller ports) to provide redundant paths and access to different storage resources for a single initiator.

A name server is a core component of the Fibre Channel fabric itself, not a device type that is included or restricted within user-defined zones.