Export Inline ForeignKey entries from parent model using import-export in Django admin

So I'm trying to use import-export to export inline OrderEntries from the parent Order model in Django's admin into a csv or whatever. I don't want to have to register the inline model with Django (which works somewhat ok), but rather using the import-export's resources module, export directly from the parent Order model's list view in Django's admin. I couldn't find any way to do this in any of the Stack Overflow posts, and some of the other resources I googled.

I tried using the ForeignKeyWidget and fields module to allow me to do this, but when I export, no data is populated.

Here are my models:

class OrderEntry(models.Model):
    order           = models.ForeignKey(Order, related_name="order_entries", on_delete=models.PROTECT)
    inventory       = models.ForeignKey(Inventory, related_name="order_entries")
    quantity        = models.PositiveSmallIntegerField(default=1)
    subtotal        = models.DecimalField(max_digits=10, decimal_places=2, blank=True, null=True)


class Order(models.Model):
    user            = models.ForeignKey(User, related_name="orders")
    order_type      = models.CharField(max_length=1, choices=ORDER_TYPE_STATUS_CHOICES, default='D')
    payment_type    = models.CharField(max_length=4, choices=PAYMENT_TYPE_STATUS_CHOICES, default='Cash')


class Inventory(models.Model):
    description     = models.CharField(blank=True, null=True, max_length=100)
    quantity        = models.IntegerField()
    item            = models.ForeignKey(Item, related_name="inventory")


class Item(models.Model):
    name            = models.CharField(max_length=40)
    brand           = models.CharField(max_length=40)

and my admin (I only have quantity as I was testing various ways to see if it would populate first):

class OrderEntryResource(resources.ModelResource):
    quantity = fields.Field(column_name="Quantity", attribute="orderentry", widget=ForeignKeyWidget(OrderEntry, field='quantity'))

    class Meta:
        model = OrderEntry
        fields = ('order', 'inventory', 'quantity', 'subtotal',)


class OrderEntryInline(admin.TabularInline):
    model = OrderEntry


class OrderAdmin(ImportExportModelAdmin):
    inlines = [OrderEntryInline]
    resource_class = OrderEntryResource


admin.site.register(Order, OrderAdmin)

If at all possible, I'd like to include foreignkey fields for the User, Inventory, and Item models when I export also. Thanks so much!