It was only after hearing that Soviet soldiers needed a good reliable automatic weapon while in hospital AND the injury to his shoulder that gave him spare time that he started serious work on unique weapon development (as opposed to modifications and improvements).
The submachinegun he designed was rejected because it was no better than the ones in service and was not so cheap to make. Its invention got him attention however because it was well designed... if he had been in a different army his weapon might have been adopted.... but this exposure got him access to better resources and factories etc which made designing easier for him.
I rather doubt his first rifle was a variant of a Garand... that would be a step backward from existing Soviet rifles like the Tokarev and Simonov rifles of WWII.
Actually, when the first AK-47s were manufactured, they were only issued to very select troops in the soviet army in 1949.
On part two your friend is wrong, the Soviets had decided to adopt a battle rifle, an assault rifle, and a LMG... the first generation being the SKS, the AK-47, and the RPD respectively. It was relatively quickly realised that the AK could do the same job the SKS could do and that the SKS was fairly redundant and it was relegated to ceremonial duties like guard duty.
The AK-47 originally had a sophisticated stamped steel receiver that was cheap and easy to make, but there were problems with durability and the receiver was changed several times. Finally the early 1950s version used a milled receiver (ie cut from a steel block) which is time consuming and more expensive and results in a heavier weapon.
The AKM didn't enter full production till 1959, the AK (they called it the AK rather than AK-47) did not really have time to be fully introduced into service with every unit, but the low cost production of the AKM meant it entered service much more rapidly, though it replaced older rifles rather than replacing the AK.
Until the AKM entered full production the AK was the standard assault rifle and was produced to replace all existing rifles... it was not like the An-94.
OFB was producing an unlicensed version and they happened to show it off in a arms fair in India, where Mikhail Kalashnikov was present as a guest. He bitched a lot about it.
How odd for him to be upset at a company stealing his intellectual property...
As noted above, the AK-47 wasn't cheap compared to the SKS, it was the AKM design that was cheap. Incidentally, the price in some African countries is much cheaper than $334 (though they usually aren't Russian origin, but cheaper knock-offs).
Legitimate rifles and rifles from "other" sources will vary in price dramatically.
Osama was seen with a short-barrelled AKS-74U Krinkov in most of his video appearances.
There is no such rifle as a Krinkov... Krinkov isn't even a Russian word. The correct designation is just AKS-74U. And that rifle is still a Kalashnikov rifle... normally seen with a 45 round magazine from an RPK-74 BTW.
Frankly, I think it is a fairly common modification for many middle eastern rich people.
Which doesn't make the assertion false.