Okay, so here's the deal: I'm playing a level 6 Gnome Paladin with a riding dog as Bonded Mount. The dog has the feats (Power Attack,) Improved Overrun and Charge Through, while the gnome has the feats Mounted Combat, Ride-by-attack and Spirited Charge.
As I understand it, when charging a foe the dog and the gnome are charging together, and while my *dog* overruns any foe that obstructs our path, my *gnome* is trained to deal extra deadly attacks during that charge. While Improved Overrun and Charge Through speak of a charge that *you* are making, Ride-by-attack and Spirited Charge specifically mention that you should be *mounted*, so I am fairly certain that so far the rules add up.
To keep things simple, my gnome never attacks a creature that my dog is opting to overrun, but we both charge the final target.
So now I get to temporarily apply 3 mythic tiers for a special scenario, and I rather like the 3rd tier Guardian path ability Burst Through, which lets you overrun any amount of characters (who may sidestep your attempt, as allies are likely to do), and if the overrun fails that creature becomes the final target of the charge attack.
But the mythic tiers belong to the gnome, not the dog. So who is doing the Overrun combat maneuver? Would Burst Through extend this special charge to the dog, or can the gnome only do this when he's dismounted? And if he does dismount and charge by himself, does he provoke attacks of opportunity due to his lack of Improved Overrun?