Sharepoint Lists adding item level permissions trouble

Hi All,

I have what seems to be a simple ask but can't figure out a solution.

Existing current access level settings:

The above settings allow the user (lets call him User A) to create and edit only items created by them.

2 questions:

1) Is it possible for User A to grant permissions to User B to edit one or more of his items?

2) Is it possible for an admin and/or list owner to prepopulate items on behalf of User A and User B and allowing then to view and edit them - keeping in mind above settings, users can only see and edit items they created

Thanks