Hopefully this data point helps someone out there.

I recently made two reservations at a Hyatt Ziva. Two club rooms on the first reservation and a standard suite on the second. Both reservations are cash stays. Since I am not in the standard suite and the suite does not come with club access, I attached a GOH to guarantee the people in that room club access. I had 6 GOHs, 5 of my own and the 6th was gifted. Wanting to use the gifted GOH and not knowing which GOH was going to be pulled had I directly applied it to the booking, I called in to have it applied after the fact. The agent could not tell the difference between the GOHs at first but eventually figured it out and applied the gifted GOH. While we were still on the phone, I saw that the gifted GOH was already gone and a little yellow Globalist Benefits icon was now showing on the reservation after refreshing the website and app.

Separately, when the property reached out to me about something else, I used my response as an opportunity to ask about club access for the third room and they confirmed that all guests coming with me will have club access. And if the GOH somehow fails to work at check in, at least I have written confirmation saying that everyone should have club access.