Help with a winged hussar themed build

[Anger Nogar]

In an 18th level one shot we are doing soon I got inspired to make a winged hussar themed character. I know that the Luring Cavalier is pretty much made to emulate this, but my last character already was a cavalier, so I want to try magus this time, since I am a gish fanboy and find the purely martial melee combat a bit boring.

Although riding and lance fighting should be present in my build, I want to focus mostly on swordplay since I enjoy it the most. I am using rapier instead of a scimitar (although the later is probably closer to cavalry sabre) since fencing grace does not have the slashing grace limitation for spell combat.

25 point buy, Dual Talent Human Kensai Magus 13/Lore Warden 5;
Traits: Magical Knack, Bruising Intellect, Magical Lineage;
Drawback: Pride;
Str 8, Dex 26, Con 12, Int 28, Wis 12, Cha 15;
(haste and greater magic weapon included in the stats)
AC 52, Touch 34, Attack +34/34/29/24, Saves: 19/19/16;

Feats: Weapon Finesse, Weapon Focus (Rapier), Greater Weapon Focus (Rapier), Fencing Grace, Rime Spell, Enforcer, Dazzling Display, Shatter Defenses, Skill Focus: Intimidation, Combat Expertise, Improved Trip, Greater Improved Trip, Advanced Weapon Training: Defensive Weapon Training, Arcane Armor Training, Flag bearer.

Magus Arcana: Flamboyant Arcana, Arcane Deed: Precise Strike, Maneuver Mastery: Trip

Spells Prepared:
1: Blade Lash x 3, Grease, Rime Spelled Frostbite x 3
2: Frigid Touch, Mirror Image, Glitterdust, Web, Bladed Dash x2
3: Haste, Fly, Vampiric Touch, Displacement, Greater Magic Weapon
4: Greater Invisibility, Arcana Theft, Greater Bladed Dash x2
5: Wall of Stone, Monstrous Physique III

Items: Manual of Quickness in Action +2, Belt of Incredible Dexterity +6, +1 Keen Cruel Dueling Spellstoring Merciful Rapier, Celestial Armor, Ring of Protection +5, Cloak of Resistance +5, 9 x Pearl of Power I (5000), 2 x Pearl of Power II, 4 x Pearl of Power III, Pearl of Power IV, Headband of Vast Intelligence +6, Wayfinder + Dusty Rose Prism, Circlet of Persuasion and Alluring Charisma +2, Stone of Good Luck, Elvenkind Boots of Speed, Dusty Rose Prism, Cracked Pale Green Prism, Amulet of Hidden Strength and Natural Armor +5, Gloves of Dueling, Obsidian Steed Figurine of Wondrous Power, Effortless laced +1 Spellstoring Agile Lance.

My main problem are:
The remaining 5% arcane spell failure (Arcane Armor Mastery will cost me 2 feats since I don't have medium armor proficiency). Is there something similar to the celestial armor that keeps its high Dex bonus, but has 10% ASF?
Picking some better lvl 5 spells. Can any more experience magus offer me some assistance here.
Increasing my attack bonus for use with Opportune Parry and Riposte and hitting in general. The Fenser trait comes to mind, but I don't really have free trait or feat to pick it up. Is there some item that gives bonus to opportunity attack rolls?

[Avaricious]

Um... with the exception of the lance and the figurine, you are a Magical Rapierist. To be fair, however, at some point the Winged Hussars did employ Estocs, which are a very loose earlier analog to the rapier (in this case punching through armor and not just flesh).

Winged Hussars evolved through Light and Heavy forms of cavalry in Poland's history as a Cavalry power. Celestial Armor could mimic the fabricated wings the Hussars wore, but the Cavalier's Banner fulfills that metaphor and occupies the same slot to boot.

"Winged Dragoon" may be a more appropriate way to describe your concept; yours is already well thought up of, and boy do I miss that 25pt buy from 3.5 days ^_^.

[Anger Nogar]

Also I plan to use my exotic weapon proficiency for some pistol, mostly for the flavor.
I don't really have any other feats to waste on firearms - it's mostly a flavor choice and me having no other use for the free EWP from Kensai, but if someone has an idea how to make that firearm attack somewhat useful I would appreciate it. I though about named bullet, but it is not really all that useful for a character not already specializing in firearms.