Remember in the May actions it was predominantly Manchukuo 'Militia', not the Kwantung Army that was involved in the opening skirmishes, the Kwanttung support was to sent 2 infantry regiments against a cavalry force (because at the time it was only a very small cavalry force before it gained reinforcements). This is telling because it describes how much that terrain and strategic mobility matters in this region of the world at the time.
Completely off the mark. The ukrepraion and the Mongols were the only thing that faced several battallions of regular Kwantug troops for a fairly long period of time, the rest of the division wasn't there not because it was being held back but because it simply didn't arrive in time.
The Japanese Airforce was also ordered at some point not to fly missions from Tokyo after destroying a Russian airbase.
That's great, except the Soviets regained the initiative fairly quickly afterwards and never lost it even after the Japanese started flying in earnest. And that's even not answering the question of "can the Japanese actually put their air superiority to good use in a land war".
In terms of the failings and successes, the critical aspect was in strategic mobility and the ability to concentrate force, seen at both the beginning and end of the engagements, and in the perceptive leadership from Zhukov, and poor leadership from whatever that Japanese commanders name of pushing the attack before logistics.
You don't say!
Except not really. It was a thoroughly systemic failure. The Japanese unit commanders, the NCOs, the men, were all trained with the focus on getting to grips quickly and were repeatedly told about Soviet inferiority (moral, operational, in terms of seizing initiative, and also in close grips). It was pretty much the sum of their training manuals for troops AND officers. Their reports (even as they are getting slaughtered by Soviet artillery) still speak about that once or twice they bayonetted someone in the trenches. At unit level! And they learned nothing at all from it, in terms of documentation except "The Soviets have good tanks, we need MOAR GUTS (and send us some artillery plox)"
Finally, the overall commander of the operation was suppsedly Kwantung Army's expert on the Soviets.
So Halhin Gol's defensive phase is completely expected, it's the counterattack that will not be guaranteed (less tanks, lesser commanders, lower quality of Soviet pilots, etc.)
But even without a counterattack, it's rather evident that the Japanese didn't have the nous to conduct operations in the middle of nowhere when opposed by the Soviet army.
If we had seen a full scale attack on the Soviet Union its is highly likely that the IJN would have staged landings in/around Chumikin(sp?), Okhotsk and Magelan(sp?) being key strategic areas in the Soviet coastal rear, Okhotsk being the head of a connecting railroad to the Trans-siberian line. With that gone, the Soviet airbase/depot at Tyndski(sp?) is crippled and the Japanese have the opportunity (if they capture Russian rolling stock) to use that line to capture and supply an advance in the north.
Okhotsk is nowhere near the Trans-Sib. Magadan is a bit important but not terribly. Finally the Japanese spreading out in the Okhotsk sea seem like the perfect time for Soviet subs to go hunting. It's huge!
Tynda is as far from Harbin as Halkin Gol. It's almost as far from the cost, and very very far from Okhotsk.
No, the key is Vladivostok, and Vladivostok is a naval fortress of such size and good positioning that no nation tried taking anything vaguley similar at all during the entire naval history of WW2.
Without the Japanese land army, Vladivostok will endure.
The Army likely won't get there within any reasonable amount of time.