I am so sorry, but there's errors in your interpretation.
1) Android is the complete system in and of itself. In "olden" times (relative to Android's age), there was a patch set that had to be applied to the Linux kernel, but that's being folded back. Android is not only the patchset, nor is it all in the kernel. Linux is only
the kernel, whereas RedHat, Slackware, Debian, Ubuntu and, evidently (under my reasoning), Android, are groups of tools around the Kernel.
2) A "fork" in and of itself happens when one takes some working code and splits it off into "his" application/structure/OS, without wanting links to the "parent project". Anyone can actually fork the Linux kernel. To an extent, Android had effectively "forked" the Linux Kernel until the re-acceptance process began.
3) Technically, yes, all the major OEM Android "readaptations" are forks in and of themselves. What separates those "forks" from Aliyun's Fork is that they pass the Acceptance tests, and are labled as Android versions instead of forks. Like Ubuntu being a Debian derivative, Kubuntu being a Ubuntu derivative, Xubuntu a Ubuntu derivative also, and so forth.