I have two WOW accounts. One is a collector’s edition that is basically a time capsule from vanilla. My current WOW account was created when I returned to the game in WOTLK. A few weeks ago I opened a support ticket with Blizzard to inquire about merging both accounts. I was told this was not a thing anymore and that both of my accounts are viewed as one account now as far as the pets are concerned. This was not the case, my live account did not have the pets. Blizzard put 1 day of service on my old account and logged into it, saw I had the pets and pushed them out to my live account as well. Cool.
I also have closed beta access on my WOTLK account. I believe this is due to both accounts being viewed as “one” account. But anyway. I do not have the pets on the closed beta. I saw a post on reddit of a stress tester who had the pets so I also checked on the stress test and the quest item was not present on any characters I made. I opened a new ticket with Blizzard and they said they do not have access to beta characters and advised I open a forum post here.
I believe what is happening is likely my collector’s edition account would have the pets, I may ask blizzard to put 1 day of service on it so I can test for you all. I realize this is a niche case but I think clarification would be good on whether or not the pets are available in the same manner as they are on live.