Chris main point was the "accessories", and his main issue was the sigma22. I don't see any reason that this won't work, and Kevin and Ti have stated the same thing.
Nate's point is more general. The parts and topology in this amp are very standard. I'm not sure I understand the risk. It's not like your going to find another JFET to use or something else more suitable for VAS stage. And the diamond buffer is pretty straightforward, wouldn't you agree? I would agree if we were ordering resistors, but it's not as if the semiconductors won't work in this topology. If you have a particular concern about parts and their intended use in the circuit, please let us know!