I managed to boot Windows 2000 with Clover UEFI32 and Longhorn 5472 boot files on real hardware.
Only problem is, no screen. But sound and disk activity exist and heard Windows sounds. Even GTX980 driver does not display (both in legacy and UEFI boot with longhorn files. But displays normally with ntldr). This problem does not happen in XP. It displays correctly.
@reboot12 @Dietmar maybe you guys can solve with patches.
For NT4, it wants kdcom.dll and bootvid.dll. If these files bypassed or patched, it can boot with UEFI.
EDIT: Display worked when I switched DP to HDMI for win2000! For NT4, I managed to bypass kdcom.dll but this time, 0xc000007b bootmgr kernel error (not BSOD). Maybe it requires ACPI or bootmgr should look non-ACPI hal.
EDIT 2: Tested also with QEMU and it worked. Video: https://youtu.be/NLW0Eg1nDNU