Explanation:

Box 1: Yes
Delta query lets you query for additions, deletions, or updates to users, by way of a series of delta function calls. Delta query enables you discover changes to users without having to fetch the entire set of users from Microsoft Graph and compare changes.
Box 2: No
Tracking user changes
Tracking user changes is a round of one or more GET requests with the delta function. You make a GET request much like the way you list users, except that you include the following:
The delta function.
A state token (deltaToken or skipToken) from the previous GET delta function call.
Delta tokens are only valid for a specific period before the client application needs to run a full synchronization again. For directory objects (application, administrativeUnit, directoryObject, directoryRole, group, orgContact, oauth2permissiongrant, servicePrincipal, and user), the limit is 7 days.
Box 3: No
There is limited support for $filter:
The only supported $filter expression is for tracking changes on a specific object: $filter=id+eq+{value}.
Box 4: Yes
Reference:
https://docs.microsoft.com/en-us/graph/api/user-delta