As for the first part of your question, I know of none, but I know very little outside the rules.

As for the second question,

Variant 1 is correct

An awakened animal retains all Animal features, features being a game term that encompasses HD, BAB and Saves.

The spell description states

An awakened animal['s] type becomes magical beast (augmented animal).

Looking at Augmented, we get

A creature with the augmented subtype usually has the traits of its current type, but the features of its original type.

Since awaken does not specify differently, an awakened animal is a "usual" Magical Beast (Augmented Animal), meaning it has the Features of an Animal paired with the traits of a Magical Beast.

Features
An animal has the following features (unless otherwise noted in a creature’s entry).

• 8-sided Hit Dice.
• Base attack bonus equal to ¾ total Hit Dice (as cleric).
• Good Fortitude and Reflex saves (certain animals have different good saves, for instance dire animals have good Fortitude, Reflex, and Will saves).
• Skill points equal to (2 + Int modifier, minimum 1) per Hit Die, with quadruple skill points for the first Hit Die.

Traits
A magical beast possesses the following traits (unless otherwise noted in a creature’s entry).

• Darkvision out to 60 feet and low-light vision.
• Proficient with its natural weapons only.
• Proficient with no armor.
• Magical beasts eat, sleep, and breathe.

Note that by RAW, the replacement of the Animal traits with that of a Magical Beast means that animal loses proficiency with all armor, even if it was war-trained prior to its awakening.

Animal companions advance only as animal companions; NPCs (including former animal companions that are permanently anthropomorphic) gain levels only by GM decree

A druid's animal companion advances only as an animal companion. An animal companion that's the target of the spell anthropomorphic animal advances as an animal companion. (The spell doesn't change the creature's type, and the rules for animal companions with Intelligence scores greater than 2 can be found here.) So far as I am aware, only PCs gain XP and, therefore, class levels: "As player characters overcome challenges, they gain experience points" (emphasis mine). Once introduced into the campaign, NPCs' levels and Hit Dice are fixed unless the GM intervenes. (Although some options—like the spell awaken—are available to player-characters for mucking about with NPCs , these are rare.)

A former animal companion who's been the victim of the spell anthropomorphic animal and the spell permanency would be, with the GM's permission, an interesting choice as a druid's cohort gained from the feat Leadership, although the looming threat of reversion due to an errant dispel magic can't be ignored.

You can read more about anthropomorphic animal companions in Paizo messageboards threads from 2011 and 2012.