8. Unusual tidbits - just evaluate them from an offensive point of view, they will make sense.
Like the Plinsk Flotilla in the middle of the marshes of Belarus or the previously mentioned mountaineers. They all have their use if we assume they were prepared for attack, they were placed there for a reason.
In case of the Plinsk Flotilla it's existence become clear when the canal, which was built from Plinsk to Kobrin, from the Dnieper to the Bug, is pointed out. They could sail up on it and go on offense. After the German attack the canal was blown up and the Flotilla was disbanded. But the canal was redug when the tables turned, a flotilla was formed, and moved up on that canal. The units of this flotilla was seen the end of the war in Berlin - attacking from that position wasn't a fool thing.
Ammo, equipment and fuel was kept close to the border, often on railroad cars where they were vulnerable, but it is advantageous during an offensive campaign, easier to move it after the advancing troops. Especially when the enemy has no time to destroy railroad lines, because caught by surprise with the attack.
As the FSE occupied it's place in the frontier the commanders from upstairs came to the front and reconnoitered the land in front of them personally. For weeks, very thoroughly. Some command posts were set up so they can see the other side of the border well. High ranking leaders flew over German territory to see what's up below. They said they did it accidentally. Observing the land in front of the units only needed for an offensive war. On defense the land behind needs to be sized up. Btw German commanders did the same.
Stalin becoming the head of government on 6 May 1941. This was a highly unusual event. He did everything to keep himself away from responsibility. He built an extremely centralized hierarchy with himself on the top but he always remained out of the spotlight, made decisions but relegated the responsibility. As we say it, he liked to slap the stinging nettle with someone else's dick. With this move now he stepped out into the lights, it was unusual for him. But there weren't a reason for it, no internal, no external. But one day before came the "5 May directive". The plans in a red envelope that was sent to every army HQ and put into a safe with the command: wait for the order to open it, and do what it says. He was meant to give this order as a head of the government, in the open watched by the whole world. He wanted to be remembered as the person who gave the order that started the liberation of Europe, or even the World.