If getting all your pets up in levels is a key for you, get a Curious Wolvar Pup, stone it, get it to level 25.
Take it to Feralas, around Dire Maul.
Find the Nether Faerie Dragons.
Pick any 2 level 1 pets.
Round 1: Insert first level 1 pet, use random move.
Round 2: Switch to second level 1 pet, take a hit.
Round 3: Switch to CWP.
Round 4: Use punch vs the dragon to oneshot it.
Round 5: Use maul on the second pet, usually a critter to oneshot it.
Rinse and repeat.
Occasionally, your CWP gets dodged or misses, the NFD uses its dodge move Evanescence, or you get a rare that has enough HP to not be oneshot. The longest fights I ever had were with bad RNG and lasted maybe 8 rounds.
You will instalevel 1 to 3, then like one level each fight for the 2 pets until 7. It took me I think 15 fights to go from 1 to 10, and with battles that fast, it takes no time at all. Once you learn the spawn points around Dire Maul, you fly point to point really fast, and they all stay the same, no animals share the same points, and after each lap everything has respawned.
You may aggro an ogre or a hyena, but any toon over 60 should oneshot them too. Once you have whatever pets you want leveled to 10, move on to subbing them on trainers, or go to Dragonblight and use the Dragonbone Hatchlings around the Wyrmrest Temple, and throughout Dragonblight.
If you want to hunt rares while leveling your lowbies, use a Terrible Turnip with weakening blow, same rotation as above, and use the weakening blow on any rare low level wild pet to one HP, then capture it. If the second pet is what you are after, use TT and weakening blow to take the first pet to 1 HP then use another one of his moves to kill it. Then weakening blow the capture pet to 1 HP, you get the idea.
I understand the desire to capture all your pets as rares and use your lowbie pets to level with as you do this, but you will take an enormous amount of time doing so. Using a level 25 TT as a third pet for capture purposes, along with whatever pet or pets you want to level will make this process SOOOO much faster.
Also, I think breeds of pets are as important if not more important than rarity, since you can stone a grey poor quality breed 4, 5 or 6 to rare pretty easy.
While pet hunting, I do this:
1. Capture the first one I fight, almost every time, to say I got one.
2. I start looking for rares/breeds I want. (I come to Warcraftpets often to see what breeds a certain pet has, and decide which one or two breeds of that pet I want.)
3. I pay attention to the breed as I engage, to decide if I want to capture it.
4. If it is a breed I want, regardless of rarity, I capture it.
5. Hunt for a rare.
6. Keep hunting for the breed I want in a rare.