So say I have a bard with Eldritch Heritage (Draconic) and she later becomes a Dragon Disciple.
Do her Dragon Disciple levels count twice for determining her Claws power like how Animal Ally allows your druid levels to count twice for Animal Companion?
Does she instead have two instances of the Claw power now? One at Character Level - 2 and one at Dragon Disciple level?
Or does she only keep the stronger of the two claw powers?
And what does this mean for Improved and Greater Eldritch Heritage? Can she even still take them? Since now she technically has the Sorcerer bloodline from levels in Dragon Disciple, and you can't take Eldritch Heritage feats for bloodlines you already have.
My understanding is that the answer to your questions are:
Do her Dragon Disciple levels count twice for determining her Claws power like how Animal Ally allows your druid levels to count twice for Animal Companion?
No, as best I can tell. The first rule precedent is that Eldritch Heritage doesn't specifically give you the Sorcerer Bloodline, only the first power. Thus, you don't actually have a Sorcerer Bloodline before taking your first level. Alternatively, I've seen it said over and over that class features from different sources don't stack unless otherwise specified. So then, even if they granted the same class feature, you don't actually have a sorcerer level, as you only use your effective sorcerer level of your Character Level - 2 for when you use the power. As near I can tell, it's like when you have a Familiar, but aren't a wizard, so you don't meet the prereqs for the Improved Familiar feat.
Does she instead have two instances of the Claw power now? One at Character Level - 2 and one at Dragon Disciple Level?
That's how I would interpret it. Moreover, it seems a nice balance between not breaking the game and not screwing over the player.
Or does she only keep the stronger of the two claw powers?
I'm struggling to come up with the precedent, but I feel like this isn't the case.
And what does this mean for Improved and Greater Eldritch Heritage? Can she even still take them? Since now she technically has the Sorcerer bloodline from levels in Dragon Disciple, and you can't take Eldritch Heritage feats for bloodlines you already have.
But that stipulation doesn't exist on the Improved and Greater Eldritch Heritage feats. It only matters for the initial Eldritch Heritage selection. Moreover, Dragon Disciple doesn't even gain the Draconic bloodline, only the associated powers. Thus, what you have is two "copycat" abilities which mirror having a Draconic Bloodline, but aren't the Draconic Bloodline.
'Course, that's my opinion. Maybe someone knows of a FAQ that makes my arguments invalid, but as I said before, this seems to be interpretation that won't break the game and won't screw over players who want early flavors of dragon in their characters that can then grow into the central focus of their powers.
Your eldritch heritage turns off now that you no longer qualify for it.
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And what does this mean for Improved and Greater Eldritch Heritage? Can she even still take them? Since now she technically has the Sorcerer bloodline from levels in Dragon Disciple, and you can't take Eldritch Heritage feats for bloodlines you already have.
Actually, Dragon Disciple does not give you the Draconic Bloodline. Like the Eldritch Heritage feats, it only gives you Bloodline Powers.
Blood of Dragons: A dragon disciple adds his level to his sorcerer levels when determining the powers gained from his bloodline. If the dragon disciple does not have levels of sorcerer, he instead gains bloodline powers of the draconic bloodline, using his dragon disciple level as his sorcerer level to determine the bonuses gained. He must choose a dragon type upon gaining his first level in this class and that type must be the same as his sorcerer type. This ability does not grant bonus spells to a sorcerer unless he possesses spell slots of an appropriate level. Such bonus spells are automatically granted if the sorcerer gains spell slots of the spell's level.
Since you don't have a Draconic Bloodline, there is no problem with getting the benefits of Eldritch Heritage (draconic) separately.
No, as best I can tell. The first rule precedent is that Eldritch Heritage doesn't specifically give you the Sorcerer Bloodline, only the first power. Thus, you don't actually have a Sorcerer Bloodline before taking your first level. Alternatively, I've seen it said over and over that class features from different sources don't stack unless otherwise specified. So then, even if they granted the same class feature, you don't actually have a sorcerer level, as you only use your effective sorcerer level of your Character Level - 2 for when you use the power. As near I can tell, it's like when you have a Familiar, but aren't a wizard, so you don't meet the prereqs for the Improved Familiar feat.
That's the only part I really disagree with, as both give you effective sorcerer levels, and effective levels always stack (it's why Animal Ally is OP).
And just a head's up, everyone with a familiar (except Shamans) can qualify for Improved Familiar, it was errata'd quite a while ago.