A 3dsx is just an arm11 userland executable and we need an arm9 kernel exploit to run CFW. All known arm9 exploits were patched in 9.2 that's why downgrade is needed.
We don't. A9LH runs so early in the boot process that we can patch the required checks before sysnand boots, rendering emunand unnecessary.
Menuhax runs within the home menu. It can't run until the home menu is starting. A9LH makes this unnecessary as the patches are already done by then.
I think there is a project to replace the home menu, but this would not provide any additional permissions, only provide a new front end.
I think you're confused. CFW requires the arm9 kernel to be exploited in order to run. The exploits which allow this to happen either run through A9LH, or through a 9.2 exploit. You can't just replace things on >9.2 and expect it to work.
If you're running on sysnand 9.2 then you can absolutely use CFW from a 3dsx. Luma, for example, provides a 3dsx loader which is launched by menuhax (or manually from the HBL).
