[Jack Simth]

Technically, RAW, that works, but it's not balanced.

Said Ape (with the 40 gp leather Barding) would be looking at AC 19, 2 Claws +9 for 1d6+6 and Bite +4 for 1d6+3, saves +7/+8/+3, HP 6d8+15 (42), a bonus feat, and natural reach.

The DMG NPC Barbarian 5, when raging (which he can only do twice per day), is AC 16, Greataxe +12 for 1d12+7, saves +7/+3/+4, HP 53.

Ape hits the barbarian on 7/7/12; average damage per round, ignoring crits, of 14.875; the raging barbarian is expected to go down in about 3.5 rounds.

Barbarian hits the Ape on a 7, for an average damage per round, ignoring crits, of 11.4; the Ape is expected to go down in about 3.7 rounds.

If the NPC barbarian makes the Ape his dodge target, and/or uses the ideal amount of Power Attack, the barbarian will barely win in a straight-up slugfest (although it will be close). But the Ape has evasion, natural reach, a higher Dexterity modifier, and a better grapple check (which makes the Greataxe useless); in a close-quarters fight, the Ape is probably going to win. In a distance fight, the Barbarian is liable to do better thanks to the longbow.

Neither case includes the Druid having any impact on the encounter (Magic Fang, Barkskin, and so on). A class feature should not be matching an entire class at it's specialty with one feat added.

Edit:
That said, in filling multiple roles, we will be stretching the two actual characters, and it'd be a useful advantage.