Pacakage in the object type definiton refers to Oracle PL/SQL package where you can organize functions and procedures under a namespace. This is generally the same name as the object type.
In postgresql it would be the same as the first half of the function names before the double underscore.
1) In this case, would leads and loans obligatory be objects of the same object type?
Sorry but that doesn't make sense. They have different attributes moreover they are different objects. In my head they should have different object_types as well.
2) Must I write them on different packages?
That doesn't feel the best way to go either.