1) no its not, it's an external brick like the BFL jalapeño had.
2) it probably is. Likely about 15% the weight of the final package
1) That's what I said :/
2) Its probably not even 15% due to the heftiness of the U3 and the packaging. But even at 15%, its not going to make a huge difference to the shipping.
As I've said above, we evaluated adding a second SKU and determined it wasn't worthwhile. Now if several people were to come together and show that they'd order a few 100 of that SKU, then Bitmain can reconsider it. But again, its not going to have the cost benefits you're expecting.