1, 2 and 3 could all be shown on the same layout. You don't have to use different layouts for each.
Show All Records is a menu option and also a script step that can show all records in the layout's table. If your layout is based on the inventory table, that should be all that you need.
For items 2 and 3, it would seem that you can perform finds with specified search criteria that find the inventory records for all items currently checked out or all items currently checked in.
These can be finds you perform manually by making menu choices are you can set up scripts to perform the finds for you at the click of a button or at the selection of a value from a value list.
But the precise details of how you might do that depend on the design of your database--which is something that you did not describe in your first post here.