Another thought: Rather than it being introduced directly from Japan or a similar style developing independently, Korean culture has made great waves in much of Asia the past decade and a half and there was a large Korean population in the USSR. Get a less crazy government in North Korea that is a bit more open and remains more prosperous than the south and perhaps manhwa aenimeisyeon (As referenced in the original post) becomes all the rage with Soviet youth and Korean-influenced studios, sometimes partnering with established counterparts in Pyongyang, begin churning out imitations in cities like Almaty, Khabarovsk, and of course Moscow. As Vladivostok was closed to foreigners, Khabarovsk becomes the center for economic and cultural interchange with China and North Korea, and because of this soon becomes the capital of Soviet animation, despite the displeasure of more artistic animators like Yuriy Norshteyn.
While the painstakingly produced artistic shorts of Norshteyn and his contemporaries remain the face of Russian animation in the west, aenimei, as it's devotees and it's Soviet practitioners call it is avidly consumed by Soviet youth, partly thanks to the use of manhua style imagery by another Koryo-saram artist, rocker Viktor Tsoi. Due to the strong symbiosis with North Korean producers it has also become a common captive import there and been distributed into China, the other Eastern Bloc states, and even Finland where it has gained an underground cult following.