In case someone might find it of use, here's my current build:
Charging Sanctified Slayer Build
As usually, the build idea is to take advantage of the Spirited Charge doubling all your damage on a Charge - and Mythic Charge + Living Ram + Boots of Stampede + Resounding Blow providing even more damage.
Travel Domain with Domain Zealot is used to be able to Swift teleport trough the battlefield to find optimal positions for charging - even every round, when so desired.
Race: Kitsune, obviously.
Mythic path: Intended for Aeon for the bane synergy and the efficiency of spamming many attacks with dispelling effect attached, but should be compatible with most.
Strong points: Good initiative and potential for high Stealth means you're usually able to get the jump on the enemies - often eliminating the most dangerous one. Kinda like an assasin - an actually effective one; High single target damage; High mobility; makes the enemies weak and vulnerable via the Aeon dispells and other abilities.
Not so good: Need to wait till Mythic Rank 2 (around level 8) to get Dex to damage. But a strong pet will help you contribute regardless, by level 5 you can start using Spirited Charge to deliver 1, potentially nasty attack, next level you get access to Bane and soon you start stacking sneak attack bonus damages as well. So it never really felt weak/underperforming.
Stats:
Strenght: 10
Dexterity: 19
Constitution: 14
Intelligence: 14
Wisdom: 14
Charisma: 8
For sure a Str version is also possible, but I wanted to try something different. I very much appreciate the high Initiative and skill synergies. Also using Reduce Person is natural to mount a Medium sized mount.
Background: Acolyte.
Level 1: Sanctified Slayer (Gozreh/Erastil, Animal Domain) Weapon Finesse
Level 2: Sanctified Slayer
Level 3: Sanctified Slayer Two Weapon Fighting; Teamwork: Precise Strike
Level 4: Sanctified Slayer: Animal Companion: Leopard?
Level 5: Sohei Monk Boon Companion; Spirited Charge (!)
Level 6: Sanctified Slayer
Level 7: Sanctified Slayer Weapon Focus; Teamwork: Outflank (!)
Level 8: Gendarme (Cockatrice) Improved Two Weapon
Level 9: Gendarme Shatter Defenses; Dazzling Display
Level 10: Gendarme Indomitable Mount
Level 11: Sanctified Slayer Accomplished Sneak
Level 12: Sanctified Slayer Talent: Combat Trick: Improved Critical
Level 13: Sanctified Slayer Vulpine Pounce (!); Teamwork: Shake it off
Level 14: Sanctified Slayer
Level 15: Sanctified Slayer Improved Initiative
Level 16: Sanctified Slayer Teamwork: Allied Spellcaster
Level 17: Sanctified Slayer Selective Spell
Level 18: Sanctified Slayer
Level 19: Sanctified Slayer Mounted Combat / Destructive Dispel / Greater Two Weapon / Double Slice / Combat Reflexes; Teamwork: Back to Back / Seize the Moment
Level 20: Sanctified Slayer Talent: Combat Trick? Double Slice? / Greater Two Weapon?
Raise Mobility for the pets defenses via Indomitable Mount and Athletics for Charge damage proc with Boots of Stampede. Plus skillchecks. Inquisitor skill bonuses also greatly help with Perception and possibly Persuasion as well.
Aeon
1 Mythic Charge (!)
2 Weapon Finesse Mythic (!)
3 Impossible Domain: Travel (!)
4 Domain Zealot (!)
5 Impossible Domain: Luck
6 Improved Critical Mythic
7 Mythical Beast
8 Mythic Two Weapon Fighting / Mythic Improved Initiative
9 Ever Ready
Weapon: Can use different finessable weapons. I recommend handaxes due to strong uniques and great critical properties (make sure to turn the Rovagug Relic into one). Peacemaker looks particularly nice.
Early on the Mallander's Insult Shortsword can be very nice for a sigificant damage boost for both hands. And of course Hasty Eradicator dagger with 2 bonus attacks is very strong for an offhand. Finnean can be helpful also, of course.
A variant with Traditional Monk dip could be made to make good use of Sais with monk Flurry.
Other notable equipment: Boots of Stampede (for another proc on Charge - alongside Mythic Charge). Living Ram breastplate. Hammer of the Masterpiece. Half of the Pair amulets. Clemency of Shadows Ring, Ring of Imminent Demise. Timely Assistance belt.
Animal Companion: I like leopard a lot. Thank you for the recommendation, Desiderius

Note that as a Kitsune, you need Reduce Person to ride it (possible at level 5).
The smaller your companion is, the less of a nuisance on the front line. And more importantly, the closer to the enemy it will be able to activate a Charge and the less it will be bodyblocked or stuck in geometry. And his early high AC is just great. Later he doesn't need Barding, so has more feat flexibility too.
If you find the need to use Reduce Person a nuisance, go with another, preferably somewhat tanky and not too bulky, companion.
Here are the proposed feats for leopard, defensive focus:
1. Weapon Finesse
2. Fury's Fall
3. Dodge
4. Outflank
5. Improved Unarmed
6. Crane Style
7. Crane Wing
8. Weapon Focus
9. Dazzling Display
10. Shatter Defences
OR offensive focus:
1. Weapon Finesse
2. Fury's Fall
3. Weapon Focus
4. Outflank
5. Dazzling Display
6. Shatter Defences
7. Dodge
8. Improved Unarmed
9. Crane Style
10 Crane Wing
Bully to support the free Trips on with Fury's Fall. It will also need 3 Int for Ouflank and Improved Unarmed Style for Crane Style, so either add 1 point to Int ASAP or have it wear an Int tiara (Bookworm's Headband is nice for the Compulsion immunity).
A nice idea, particularly if you have more animal companions in your party, is to either have an Oracle with Nature Mystery and Friend to Animals Revelation - or dip 1 level oracle on a high Charisma character (like Ember, maybe Seelah) for that Revelation. It will greatly boost the saving throws of your pets.