Django-Selectables will work in the admin. To get started on integrated the fields and widgets in the admin make sure you are familiar with the Django documentation on the ModelAdmin.form and ModelForms particularly on overriding the default widgets. As you will see integrating Django-Selectables in the admin is the same as working with regular forms.
In our sample project we have a Farm model with a foreign key to auth.User and a many to many relation to our Fruit model.
In admin.py we will define the form and associate it with the FarmAdmin.
You'll note this form also for new users to be created and associated with the farm if no user is found matching the given name. To make use of this feature we need to add owner to the exclude so that it will pass model validation. Unfortunately that means we must set the owner manual in the save and in the initial data because the ModelForm will no longer do this for you. Since fruit does not allow new items you'll see these steps are not necessary.
With our Farm model we can also associate the UserAdmin with a Farm by making use of the InlineModelAdmin. We can even make use of the same FarmAdminForm.
The auto-complete functions will be bound as new forms are added dynamically.