The Fire Pet has a group buff, I believe it's a proc.
Even with an Adept 1 upgrade, the Air pet died very quickly - that was the last time I used it.
Once parsers scrub the numbers and databases are built, we will know the exact HP, AC, DMG and spells of all pets. Until then, I'll stick to the Earth pet.
Here's a good site for summoners. Lot's of discussion and parser info.