How does a Dragonrider work with a Draconic exemplar?

Hello. I have just recently started to play pathfinder and to say the least the amount of information is sort of daunting in the start. That being said Im not new to roleplaying and while rules can be learned if you just do your homework (This is part of said homework) I have the opinion that the rules should serve the roleplay.

The other day I read up on the Draconic Exemplar Racial paragon class when I noticed that they could use a sadle as equipment. This got me and a friend thinking. Can you play as a Draconic exemplar serving as a mount to your knightly friend?

From what I understand the rules permit the riding in and of itself ( http://archive.wizards.com/default.asp?x=dnd/rg/20050222a look under intelligent mounts) but my question is how the Dragonrider (Or other classes with mount based abilities) work with the Exemplar. For example does the dragonriders "Link" or "Shared spells" abilities work with the exemplar if you have stated that the exemplar is your bonded dragon mount.
Another question is if such a rider would need a riding skill since from I can tell it only affects controlling your mount. (And the rider can ofcourse not control the Exemplar mount since its a player. That depends on how much of an asshat the Exemplar decides to be.

And lastly how would combat work. If the dragon charges can the rider use his lance for the damage amplification (Even if its not the riders turn) or should you wait for the riders turn (And if so can they still use the bonus damage?) Can this be fixed by the two players acting on the same initiative and doing their turns simultaneously? And lastly (At the time of writing I havn't found rules on the normal riding for this so sorry if this is covered elsewhere) how do you calculate damage for the rider and dragon. Does melee attacks only targed the dragon since they cannot reach the rider or do the attacker chose target? (Ranged attack should work as normal I figure)

Wow this was one hell of a wall to start of with as my first post. But I hope you guys can help me and my friend out.

The Dragon rider should have a set list of mounts. If you don't want to break the game with 50d6 breath weapons every 1d4 rounds, it's best to leave him to that list.

It's probably best to do this with a class that does not get Mount based abilities. Using a Paladin who took the weapon version of Divine Bond, or a Fighter, or a Magus, or some other similar class will do better (The Sohei archetype of the Monk was all but made for this situation, incidentally).

The reason is that a mount's advancement comes entirely through their owner's levels-- so the mount PC would be stuck with a pretty weak and crappy character. The other option would be to ignore the mount's advancement and just use the PC's class, which you can do... at which point, you might as well use a class that doesn't have a mount in the first place (see above).

The third option of letting the mount PC double-dip for progression is, as Kaouse noted, insanely broken.

As for your specific questions: He still needs Ride, because some options (like staying in your mount) aren't about control, but he should never need to, or even be able to, control the PC mount with the skill.

The two should move together in initiative, as mount/character pairs normally do.

The mounted character is still considered mounted, and gets all the benefits of such, including bonus lance damage.

The attacker chooses whether to target the mount or rider. Since the rider probably has Mounted Combat and that has a chance of negating attacks directed at the mount, the rider is likely to suffer the majority of attacks in combat.

you will suffer from turn order discrepancies if you have two players playing in a mount-mountee relationship. best go for leadership feat and make him a cavalier and he just rides his horse when not trying to be awesome.

what's supposed to happen is the mount has the rider's turn and follows all of the riders instructions, else the action economy breaks.