It peaked at 4.05% in March. The last 2 months it went just below 4% as the Unknown category increased. For June the reverse happened, so 4.04% seems to be the real current share of Linux on Desktop as desktop clients were read properly/werent spoofed.
Android is as Linux as every other Distro is.
Yes because that’s actually what Linux is. A kernel. There are also no such things as “Linux applications”. Different distros use different package formats. If you mean ELF binaries you can certainly run those. Android in it’s typicall configurations tried to prevent that because it would be a huge security vulnerability if apps could just run random ELF binaries, but if you root your device you can run those.