Love it..
From a grill point of view, it might be worth adding some small holes along the bottom plate to allow air in to keep the fire going.
Maybe some holes on the side plates.
***
Coals wil burn ok with a flat bottom, but wood will start getting a bit Smoky if it hasn't got enough airflow to keep the flames burning from underneath.
****
I have no idea about the bag, though I did say another barbecue very similar to this on eBay where the curry case was made from wood!!!
And don't forget the pins and r clips to keep it all stacked together neatly.