There's no need to create a second account on WarcraftPets or add a second character. All pets are account-wide now, so any pets you collect on an alliance character will automatically be added to your overall collection. Importing your collection from the armory will include any and all pets that you've collected (that are on the armory), regardless of your faction.
Feel free to browse through Perks N Peeves
, my vanity pet collecting blog!