What follows are examples and advice on how the Merits and Flaws from other Changeling sourcebooks can be used in relation to pooka.
Acute Senses (1 point Merit)
This is a no-brainer. Most animals have senses sharper than a human or changelings (except maybe sluagh). This simple Merit can be used to reflect the keen sense or senses a pooka's animal affinity if renowned for. A bloodhound pooka could have Acute Smell, a hawk pooka might have Acute Vision, and so forth. Such a Merit applies in both the pooka's fae and animal miens.
Ambidextrous (1 point Merit)
Really only found among monkey and other simian pooka, as no other animals have hands....
Animal Magnetism (1 point Merit)
Who better than someone part animal to have such a Merit? This goes well for animal affinities noted for sexuality and fertility (tigers and bulls, for example).
Art Affinity (5 point Merit)
For pooka, this would most likely be with the Primal Art, as it speaks to the kith's deep connection to nature. Chicanery and Legedermain are also common, as they have great use in pranks. Metamorphosis is a possiblilty, given the pooka's natural ability to shapechange.
Bad Sight (2 point Flaw)
Mole pooka, anyone?
The Bard's Tongue (1 point Flaw)
Interestingly, no pooka has ever been known to have this Flaw. This is probably because their inability to speak the truth prevents it.
Boon of Fate (1-5 point Merit) from War in Concordia
Pooka are as likely to have this Merit as any other Kithain.
Changeling Eyes (1 point Flaw)
Pooka almost always have animal-like eyes in their fae miens, and sometimes it leaks over into their mortal seemings. Did that woman really have cats eyes, or was it your imagination?
Color Blindness (1 point Flaw)
Several animals are noted to be color blind, particularly dogs.
Commanding Voice (1 point Merit) from War in Concordia
This could be found in Pooka with affinities for animals representitive of command and leadership, such as bald eagles. Animals with powerful voices would work as well, such as wolves and elephants.
Common Sense (1 point Merit)
Often, humans seem to display less common sense than animals, despite superior intelligence. Brains and wits do not always go hand-in-hand. Animals survive on instinct, and instinct is in many ways a form of common sense ingrained in the animal's genes. Pooka can benefit from this natural pragmatism.
Confused (2 point Flaw)
Animals can easily become confused when things go too fast or they come upon something they don't understand. Their instinctiveness cannot always compensate with the modern world and other disorienting things.
Crack Shot (2 point Merit) from War in Concordia
An animal affinity with great eyesight (ravens, eagles, falcons, etc.) or hand-eye coordination (monkeys) could certainly have this combat merit.
Curiosity (2 point Flaw)
Many animals are known for their curiosity. Cats and ravens, for example.
Danger Sense (2 point Merit)
Pooka with affinities for animals that have developed an awareness for predators (rabbits, for example), might have such a talent as this.
Daredevil (3 point Merit)
This is good for pooka with notably bold animal affinities. Lemmings?
Divided Loyalties (3 point Flaw) from War in Concordia
Pooka would not have any more or less reason for having this Flaw than any other Kithain. Pooka are diverse, after all, and are on both sides of the new war, as well as trying to stay out of it completely.
Double-Jointed (1 point Merit)
Pooka with affinities for highly flexible or invertibrate animals might have this merit.
Echoes (2-5 point Flaw)
Rather than superstitions about faeries, this Flaw applies to superstitions mortals have about animals. People may unconsciously go out of their way to avoid crossing the path of a black cat pooka, thus drawing attention to her. A wolf pooka might be held at bay by wolfsbane.
Faerie Eternity (5 point Merit)
Affinities for extremely long-lived animals (tortoises, for example), might give the pooka the benefit of this Merit.
Faerie Godparent (3 point Merit) from Fool's Luck
This could be seen among pooka with affinities for household pets. You might be the loyal family dog that has reincarnated with the same mortal family for generations, always there to guard and protect them. Perhaps you are the ferocious spirit-tiger that comes when summoned to defend the dynasty, as they say in the legends they pass down through their family. The possibilities are endless.
Hostage (1-5 point Flaw) from Fool's Luck
Who better to keep on a leash or in a cage than someone that can turn into an animal? Pooka are often so cute and lovable, they make great hostages for their sympathetic value.
Huge Size (4 point Merit)
Common among pooka with affinities for large animals (bears, bulls, etc.).
Iron Will (3 point Merit)
There are many animals known for being extremely stubborn. Bulls, boars and goats are noted for being rather difficult to dominate. Badgers, wolverines and even rats are notoriously single-minded as well.
Luck (3 point Merit)
Many animals are associated with luck in some manner; black cats, rabbits (or at least their feet) and so forth. A pooka with an affinity for such an animal might benefit from this perceived luck.
Mute (4 point Flaw)
Not every animal can vocalize sounds.
Oathtaken (4 point Flaw) from War in Concordia
The Sidhe might not have been as insistant that Pooka take the Oath of Loyalty as other Kithain. After all, few see the Pooka as a real threat. Still, just as many Pooka may have been enforced into the oath as other commoners. Sidhe are paranoid enough these days to not take the chance.
Perfect Balance (3 point Merit)
Cats, monkeys, spiders....several affinities are noted for their incredible equalibrium.
Phobia (1-3 point Flaw)
Animals have enemies, and its only natural that the fears extend over to the pooka. Cat pooka may be afraid of dogs, mice pooka fear cats, etc. This extend to pooka with affinities for the feared animal as well. So a mouse pooka might have an instinctual fear of that cat pooka who only wants to be friends. A fear of hunters is common for many deer pooka. Many animals fear fire.
Poison Resistance (1 point Merit)
Venomous animal affinities might also have some natural resistance to poisons as well.
Regeneration (7 point Merit)
Lizard pooka have been known to have the ability to heal quickly. Whether they can truly regrow lost limbs is unknown...
Seeming's Blessing (5 point Merit)
This merit is completely useless to Pooka. The Confidant already works on mortals, anyway, and they cannot shapechange in front of anyone at all.
Sell-Out (2 point Flaw) from Fool's Luck
It is in the nature of animals to do what they can to protect themselves. Sometimes, for pooka, this means joining the 'winning' side and being the loyal lapdog of the local noble.
Short (1 point Flaw)
Sensible for pooka with small animal affinities (mice, hamsters, insects, etc.).
Shy (1 point Flaw)
There are numerous timid animals, and pooka who have affinties for them.
Sidhe's Curse (5 point Flaw)
Considering how many pooka waited out the Interregnum in the dream-burrows, it would not be suprising to see many of them with this Flaw, as they would not have had the same long-term exposure to Banality as the pooka who stayed on Earth did.
Speech Impediment (1 point Flaw)
Pooka with big teeth or tusks would certainly have trouble speaking clearly.
Slipped Seeming (1-5 point Flaw)
This can be a dangerous Flaw, as a pooka's fa emien can be very noticable. It is very difficult to hide a tail or wings or scaly skin.
Surreal Beauty (1 point Merit)
Especially beautiful and extravagent animals (peacocks, for example), might have this Merit. Pooka like this can rival the sidhe in their beauty.
Werewolf Companion (3 point Merit)
A wolf pooka would have more reason than any other of his kith.
Winged (2 point Flaw/4 point Merit)
Bird, bat and flying insect pooka have a very obvious reason for possessing the Merit version. Pooka with affinities for flightless birds (chickens, penguins, etc.) could have the Flaw version.
Wyld Mind (2 point Flaw)
Good for notably frenetic and easily distracted animal affinities (ferrets, for example).