Pathfinder Chronicler and All These Bardic Performance-Alike Archetypes and Prestige Classes: How do they stack, in practice?

Question

So. Pathfinder Chronicler is basically "meant" to stack with your bard level for the purpose of determining your bardic performance rounds per day.

The relevant rules text of Pathfinder Chronicler, however, says it stacks with levels in any other class that grants a similar ability:

Bardic Knowledge (Ex): This ability is identical to the bard class feature of the same name, and levels in this class stack with levels in any other class that grants a similar ability.

Bardic Performance (Su): At 3rd level, a Pathfinder chronicler gains this ability, which functions like the bard class feature of the same name, except that the chronicler's effective bard level is 2 lower than her class level. Levels in this class stack with levels in any other class that grants a similar ability to determine her effective bard level.

The question, then, is how it stacks, especially when considering multiclassed Bard/PFC/X/Y, or X/Y/PFC, where X or Y may themselves have the language of the Pathfinder Chronicler's stacking effect, and what is similar enough to stack with.

At time of writing I'm pretty sure I've found all the things that actually grant bardic performances, but it's possible I'm missing something.

Levels in Bard: So obvious that we do not need to consider them except as the base case from which others diverge.

Levels in Skald: Answered here, though not necessarily for all interactions.

Sensei Monk: "A sensei’s advice is identical to bardic performance (using oratory), [...] as a bard of the sensei’s level,"

Argent Dramaturge:

Argent Performance: An argent dramaturge can use Perform (sing) to create special magical effects that hinder outsiders (particularly those affected by silver, such as devils) as per the bardic performance bard class feature. She can use this ability for 2 rounds per day for each argent dramaturge level she has, and can use rounds of bardic performance gained from bard levels to perform argent performances and vice-versa.

Sphere Singer's Starsong Performance:

A sphere singer is able to use Perform (sing) to create magical effects, as per the bardic performance bard class feature.

Battle Herald:

Inspiring Command (Ex): A battle herald uses her keen tactical acumen and decisive judgment to lead others to victory, as well as her mastery of command to assist herself and her allies in battle. All battle heralds may use inspiring command to inspire courage (as the bardic performance ability); bard and battle herald levels stack to determine the bonuses provided by inspire courage.

Oath of the People's Council Paladin: "This functions as bardic performance as per a bard of her paladin level using Perform (oratory)."

Carnivalist Rogue: Levels stack with "Levels in a class with the distraction or fascinate bardic performances [...] for the purpose of determining bonuses granted by these performances." (This interaction is probably a question in and of itself, really.)

Evangelist Cleric: "This ability is similar in all respects to bardic performance as used by a bard of the same level (including interactions with feats, spells, and prestige classes), using Perform (oratory) as the evangelist’s performance skill."

Exemplar Brawler: "At 3rd level, an exemplar gains the ability to use certain bardic performances. [...] The exemplar’s effective bard level for this ability is equal to her brawler level – 2. [...] This ability otherwise functions as bardic performance; feats and other effects that affect bardic performance (such as the Extra Performance feat) apply to it."

Storyteller Medium: "This ability is similar in all respects to bardic performance as used by a bard of the storyteller’s medium level (including interactions with feats, spells, and other abilities), [...]"

Ocean's Echo Oracle "This ability is identical to bardic performance (using Perform [sing] only), [...] as a bard of the ocean’s echo’s level."

Song-Bound Oracle: "You can perform the countersong bardic performance (using Perform [sing] only) for a number of rounds per day equal to your oracle level. If you gain the bardic performance class feature, these rounds are in addition to any other bardic performance rounds you gain, but they can be used only for the countersong bardic performance."

So. How do they stack, if they do, and why do or don't they stack? I am primarily interested in Pathfinder Chronicler, but I believe that Carnivalist Rogue is also worth special attention.

There is also the question of whether Pathfinder Chronicler stacks twice via Evangelist (or any other PrC with the "aligned class" feature, whether aligned to the base Bard or at PFC itself), or the Loremaster PrC's "this stacks with Bardic Knowledge" bonus to Knowledge checks, but those are stretching the scope of this question a bit.

So:

For characters taking multiclass levels in X/Y/Pathfinder Chronicler/(potentially) Z,

1. How do you determine which performances they can access?
2. What is their total net bonus to knowledge checks/how is that determined?
3. How many rounds of performance/performance-alikes would they have, and would those rounds be interchangeable or not in the general case (i.e. using the language "as a bard")? What about the other bard prestiges (e.g. Argent Dramaturge, which honestly I can answer 'only if you're a bard' myself for)?
4. Are there notable exceptions to the general case in which something stacks that would not otherwise?

Answer 1

Abilities don't stack unless they say they do.

No—unless an ability specifically says it stacks with similar abilities (such as an assassin's sneak attack), or adds in some way based on the character's total class levels (such as improved uncanny dodge), the abilities don't stack and you have to use them separately.

This means that unless an ability specifically calls out stacking, it doesn't stack when another class grants that ability (i.e. most of your list doesn't stack, since most is based off of the default bardic performance, which doesn't say it does).

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Concerning Evangelist

There is also the question of whether Pathfinder Chronicler stacks twice via Evangelist (or any other PrC with the "aligned class" feature, whether pointed at the base Bard or at PFC itself), or Loremaster's "this stacks with Bardic Knowledge" bonus to Knowledge checks.

I'm not sure what you mean here, but if we look at the Aligned Class class feature, we see:

Aligned Class (Ex): Evangelists come from many different backgrounds, and they show an unusual range of diversity. At 2nd level, the evangelist must choose a class she belonged to before adding the prestige class to be her aligned class. She gains all the class features for this class, essentially adding every evangelist level beyond 1st to her aligned class to determine what class features she gains. She still retains the Hit Dice, base attack bonus, saving throw bonuses, and skill ranks of the prestige class, but gains all other class features of her aligned class as well as those of the evangelist prestige class.

All evangelist does is essentially add levels to your class, there is no "stacks twice" occurring.

If you went Bard 5/Pathfinder Chronicler 1/Evangelist (Aligned PFC) 10, you would count as a level 13 bard for bardic performance (5 (Bard) + 8 (1 PFC, 9 aligned evangelist levels)).

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Concerning Carnivalist

If we look at Carnivalist, we see:

The pet performance ability otherwise functions identically to bardic performance. Levels in a class with the distraction or fascinate bardic performances stack with carnivalist levels for the purpose of determining bonuses granted by these performances.

This means that the levels only stack for the purposes of those performances.

If you went Bard 5/Rogue (Carnivalist) 5/Pathfinder Chronicler 1/Evangelist (Aligned PFC) 5, you would only count as level 13 when performing the Distraction or Fascinate bardic performances (5 (Bard) + 5 (Carnivalist) + 3 (PFC 1, 4 aligned evangelist levels)).

If you were to do the Inspire Courage bardic performance, you would instead count as a level 8 bard (5 (Bard) + 3 (PFC 1, 4 aligned evangelist levels)).