WoW Insider just blew my mind. Why didn't I think of it sooner? It's so simple yet brilliant - it's genius!
Get all Children's Week pets in one year. Not possible? Well with account wide pets in MoP, I think it is. :P
Because all pets will be shared across all your toons in MoP, by choosing one of each pet, you'll have all the Children's Week pets ready to summon and play with in MoP. The only trick is that you'll need level appropriate toons for the Outlands and Northrend quest chains.
For the Shattrath quests, you'll need characters that are at least level 60, while the Dalaran chain will require characters that are at least level 70. For the remaining four companions from Stormwind or Orgrimmar, you'll need alts that are at least level 10.
So this neat idea might not be for everyone. But I still say give it your best shot. The pets will still be around next year, and unlike the holiday boss dropped pets, these companions are guaranteed as long as you have the time to complete the quest chains. Don't stress out too much if you can't collect them all right away. They're worth waiting for!