Just as an FYI:

If you're just after the achievement, just have a friend with the raid pet cage it, trade it to you, learn it, re-cage it, then trade it back. You'll get credit towards the achievement.

I started a DK on TVC. Got a Giraffe Calf finally. Took a look for a Scourged Whelpling, but no luck. I'll check back after reset on Tues.

So far, this looks like a great strategy. Thanks for the tip!