To be clear - great work! I'm just doing a critical eye on it.
"Ferocious Attack: "
An issue I have here is that unarmored defence is more of a ribbon ability than it looks. A 14 dex barbarian in a breastplate has 16 AC; you need something like 16 dex/16 con to match that.
In a feat-less magic-item-less game at high level it could be good (as you may have bumped your dex/con up past what mundane armor can do). It is great flavor-wise. With rolled stats it can be good. And if you lose your gear it is really nice.
Second, it replaces a
defensive ability with an offensive one.
However, cats (as small creatures) cannot use heavy weapons, which makes barbarian cats crippled (as -5/+10 feat plus reckless attack is crazy good). So this kind of boost might not be bad. In fact it might not be enough.
Finally:
Whenever rolling for damage following a successful attack, roll two damage dice and choose the highest result .
should be worded
Whenever rolling weapon damage dice, roll an additional one and discard the lowest.
High Pitched Screech: While a Cat Bard can use its voice to achieve the most beautiful, musical effects, they can also do substantially less pleasant things . A Bard can unleash a hideous screeching noise as an attack (using Charisma), targeting one enemy within its line of sight . This enemy is afflicted by the Fear condition for the next turn.
I'd make word it like a cantrip. As worded it is unclear what kind of action it takes and works on deaf targets.
Note that fear is pretty strong; it is stronger than the effect from vicious mockery, as it imposes disadvantage to more stuff, and isn't just 1 check, and it restricts movement. I might have this cost a use of bardic inspiration, and do the die roll in psychic damage, and be once/short or long rest.
Laughter of the Cat: A strange hybrid of a growl and a purr leaves your mouth, bubbling through the air and leaving all who hear it convinced of your ineffable cuteness . Once per long rest, you can use this ability to convince all creatures within 15 ft not to attack you for one round .Each creature must make a Charisma savea or be unable to attack you for the next round .
This is basically sanctuary, so what I'd do is steal as much wording as you can from it.
Laughter of the Cat: As an action, a strange hybrid of a growl and a purr leaves your mouth, bubbling through the air and leaving all who hear it convinced of your ineffable cuteness. Until the start of your next turn, any creature who targets you with an attack or a harmful spell must first make a Charisma saving throw. On a failed save, the creature must choose a new target or lose the attack or spell. This spell doesn’t protect you from area effects, such as the explosion of a fireball. After using this ability you must complete a long rest before using it again.
Similar wording massage:
Feline Fine: You have an inner reserve of strength, drawn from the great song of creation that so few can truly hear. You have advantage on Death Saving Throws.
Wild Cat: You are trained in Nature or Animal Handling.
Nature’s Child: You move through the natural world with absolute ease; nothing obstructs you. You may cast the Freedom of Movement spell on yourself as an action without using a spell slot.
Paw Flurry: You can dash as a single action .Rather than have to move, and then move again as your second action, you can travel up to your full move as a single action
I have no idea what this ability is supposed to do. Dash is an action that gives you additional movement, it doesn't actually move you. This reads like a misunderstanding of the movement rules. And even then, I don't know what it is supposed to do.
At 11th level, you may take the following ability, in place of Reliable Talent:
Vicious Slice: Your claws have been honed to razor sharpness . Whenever you make a successful bite attack, you may immediately make a second attack as a bonus action .
That is (a) a trap (reliable talent is crazy awesome), and (b) a combat ability in place of a less combat one, and (c) not that good. Rogues rely on delivering sneak attack, this doesn't help.
it is unclear if that is a bonus cantrip or just an expanded selection.
Grimalkin’s Charm: Whenever you suffer damage, you may reduce the total by your Charisma modifier
No action cost?
this is used as the name of 2 completely different abilities in different classes (warlock and I think druid?)
No save?
Animal Friendship: You immediately add the spell Faithful Hound to your spellbook, if it isn’t there already . You may cast this spell without expending a spell slot .
As written, this permits you to have a 4800 hounds active by casting it each round at a new location. That spell doesn't require concentration nor does it end when you cast it again.
Artful: You are perfectly poised and exactly balanced when wielding a blade . Whenever using a weapon with the finesse quality, you gain a +2 to damage rolls with that weapon .
This is basically an upgraded two weapon fighting plus slightly restricted duelist. Note that cat natural weapons are not finesse.
If you want to have fun, make it
Artful: You are perfectly poised and exactly balanced when wielding a blade. When you make an attack with a finesse weapon or a cat's natural weapons, you can choose to make the strike artful. You take a -5 penalty to hit with it in exchange for a +10 bonus to damage.
Cat’s Paw Martial Archetype
Archetypes should have non-combat utility. This one lacks it.
Wording conflicts with the 4 hour rest cat ability. Also is unclear how you enter it (what kind of action?)