The facilities in the Ukraine are not that big either and besides, its way down in the Black Sea while the Kuznetsov is in the Barents Sea. Even if those facilities are in Russian hands, the carrier has to go around Europe, down the Atlantic, through the Med, past Turkey and into the Black Sea. Bad geography.
What the Russians have is a mobile dock that is big enough for the Kuz. Unfortunately, the dock sank because of accident but it has been floated up again. Its like that dock that Jiangnan recently completed to move blocks of 003. Maybe Russia needs more docks like that.
Electronics are highly classified, and China (or anyone else) does not transfer a ship to someone else first unless all the classified electronics are stripped, although you can leave the cabling and the network infrastructure. The Russians are free to put their own radars, EW, communications and CIWS on. In such a hypothetical transfer, the two carriers are transferred to Russia by sending them to Vladivostok, which is only a short distance away from China, and home of Russia's Pacific Fleet. The ships can be refitted there, and can be stationed there permanently as flagships for the Pacific Fleet. Or during summer, make the transit up the Bering and into the Arctic Ocean and to the Barents Sea to be stationed in the Northern Fleet. KnAAPO, an important Sukhoi aircraft facility and manufacturer, is based in the Amur near Vladivostok, and it can manufacture and supply aircraft for the carriers.
Where Russia needs China's help is finishing the Nord Stream pipeline.
