If understand the second query like, you want to know 'what all fields must be set mandatory for Notification?' It is entirely your choice. What your process demands.
- A general requirement will be the Notification Title (Short text) should be mandatory.
- One can have Equipment field empty, but for others it might be a Required field.
- Like-wise with every field.
Normally, these requirements get matured some time after the implementation.
Regards
KJogeswaraRao