I personally wrote the document that you linked above and personally developed and tested every scenario. We network boot in UEFI mode daily within VMware.
The one thing that does not work is chaining to our bootloader from GRUB, due to an issue with GRUB as previously discussed. Note that the document above does not describe any scenarios that involve chaining from GRUB, only booting mboot64 directly or chaining from ipxe to mboot64.
It would be good for us to document the incompatibility with chaining from GRUB. I wasn't aware of it the time I was working on the document. Perhaps a KB article and/or a note in the next rev of the document.
