Farina

Weapon: Hotshot Lance

Assist: Reposition

Special: Moonbow / Luna / Bonfire / Iceberg / Sol / Noontime

Passive A: Atk/Spd Catch / Heavy Blade 4 / Sturdy Impact / Swift Sparrow 3 / Atk/Spd Solo 

Passive B: Dive-Bomb / Desperation / Atk/Def Snag

Passive C: Atk/Def Rein / Spd/Def Rein

Sacred Seal: Atk/Spd Solo / Heavy Blade / Atk/Def Solo / Swift Sparrow / Life and Death

• Assuming you've fully given Farina her share of Dragonflowers and thus fully activated all of Hotshot Lance's effects, she already becomes a quite formidable attacker. Atk/Spd Catch (whose two conditions are quite easy to fulfill) and Atk/Def Rein (a nice Attack and Defense swing on every match) come by default on her and only reinforce the sheer initial value of this build, giving her a powerful yet low-investment initiator build from the get-go.
• The B slot is reserved for a skill that aids in consecutive follow-ups, either choice of which allows Farina to flurry attack enemies in a pinch without worrying about being counterattacked.
  • Dive-Bomb is preferred as it requires virtually zero setup — both Farina and her opponent just need to be over 80% HP. It coincidentally encourages Farina to maintain Atk/Spd Catch conditions — that is, the enemy being at full health — as well. 
  • Lacking Dive-Bomb or simply preferring a more classic setup, Desperation is significantly easier to access, requiring Farina to set herself below 75% HP. Note that Farina will essentially have a performance sweetspot between 25% (the minimum HP required for Hotshot Lance to be active) and 75% (Desperation range), so a bit of careful play is advised. 
  • Atk/Def Snag is technically optimal when using Atk/Spd Catch; it fulfills the debuff condition of the skill, which allows Farina to potentially reach its maximal bonus (+9) whenever another ally uses their positional Assist with Farina. If not using Catch, there's little reason to keep Snag outside of team support. 
• After considering the consecutive-hitting nature of Farina's chosen B slot as well as the cooldown acceleration from Hotshot Lance, she can run some pretty nice Special options. 
  • Moonbow's CD is reduced to 1 permanently and requires no further acceleration to activate in a single round. 
  • With Heavy Blade, Farina can afford to consider a few Specials with higher cooldown/damage instead, especially Luna, Bonfire, or Iceberg. 
  • For a Farina with enhanced focus on mixed phase combat, Noontime or Sol provides sustain and a way to keep Hotshot Lance's HP condition active consistently. 
• Other A-slot options are up for consideration, though Farina should stray away from recoil-inducing choices like Fury or Atk/Spd Push as Hotshot Lance only works as long as she's above 25% HP. 
  • Heavy Blade can be used here if you want to reserve the Sacred Seal for another unit.
  • Swift Sparrow and Atk/Spd Solo tends to offer a consistent Atk/Spd bonus if you can't fulfill Catch's conditions for any reason.
  • Mirror or Sturdy Impact provides safer initiations by boosting a chosen defense stat instead and preventing enemy follow-ups. 
• Spd/Def Rein is a nice C slot alternative which assists in follow-up potential. It can be used over Atk/Def if you're not using Heavy Blade (which would normally prefer the Atk swing coming from Atk/Def Rein). 
• In the Sacred Seal, Heavy Blade's already been discussed as a way to quickly activate Specials in a single strike. Atk/Spd Solo or Atk/Def Solo aids in improving Farina's performance in both phases, though she may run more initiation-oriented options such as Life and Death or Swift Sparrow.

Weapon: Hotshot Lance

Assist: Positional Assist

Special: Galeforce

Passive A: Atk/Spd Catch 4 / Heavy Blade 4 / Swift Sparrow 3 / Life and Death

Passive B: Dive-Bomb / Wings of Mercy

Passive C: Atk/Def Rein / Atk/Spd Rein

Sacred Seal: Heavy Blade / Life and Death / Atk/Spd Solo 

• There's little difference between this and the previous offensive build, but Galeforce deserves special mention as a Special; Hotshot Lance already decreases its cooldown to a more even and manageable 4 while giving Farina a huge offensive advantage with full Dragonflower enhancements. 
• As usual on a Galeforce build in this game, Heavy Blade is pretty much necessary in either the A slot or Sacred Seal to fully charge it with its still-pretty long cooldown. To help ensure its activation, Atk/Def Rein is preferred over little else (besides its Atk/Spd version) as it swings Atk comparisons in Farina's favor while improving her damage output. Hotshot Lance even zeroes out any possible Atk bonuses present on the enemy, so you typically shouldn't need to be choosey of matchups in most circumstances — just be wary around higher Atk enemies or those with Guard in some form.
• Dive Bomb is still advisable as it grants the ability to make uninterrupted double hits with virtually no setup, possibly charging Galeforce in a round. On setups with beacon units (such as Fury Eir or Ninja Lyn) and other Galeforce units, especially in Aether Raids Offense, Wings of Mercy is also an option to successfully continue Galeforce chains.

Weapon: Hotshot Lance

Assist: Reposition

Special: Noontime / Sol

Passive A: Distant Counter / Atk/Spd Catch / Kestrel Stance / Other High-tier Stance skills

Passive B: Pegasus Flight / Mystic Boost / Guard Bearing / Guard

Passive C: Atk/Def Rein 

Sacred Seal: Iote's Shield / Fort. Def/Res 2 / Other Solo / Stance skills

• Farina's tanking potential shouldn't be ignored either, as her already-good, balanced statline is further improved with Hotshot Lance's large universal stat boosts — it goes without saying you should invest maximum Dragonflowers for its fullest potential at this point. 
• Ideally, a Speed or Resistance Asset both do great in improving Farina's follow-up potential/avoidance or visible Resistance bulk, respectively. 
  • The latter is especially valuable in increasing the potency of Pegasus Flight, which applies an Atk/Def subtraction based on the difference in visible Resistance rather than in-combat. Since Farina's base Resistance is considered only sufficient at best, builds involving Pegasus Flight should take more steps in improving it, including deploying Mythic Heroes whose blessings raise Resistance (such as Eir and Dagr) and running Fort. Def/Res 2 in the Sacred Seal. 
• Distant Counter allows Farina to make mileage of this build's more defensive focus by counterattacking ranged units. For obvious reasons, matchups against bow units should be avoided unless you choose to use Iote's Shield in the Sacred Seal. Of course, you can simply eliminate such threats with other allies and free up her Seal for other useful things.  
• For a more melee-oriented take on the build, Farina's native Atk/Spd Catch can be used for potent offensive boosts in both phases, and an accompanying Solo skill along with it for maximal mixed phase performance. A high-grade Stance skill like Kestrel Stance 3 or Sturdy Stance 3 is also worth considering as they provide a built-in form of Guard. 
• If Pegasus Flight is not in your cards for any reason, Farina can turn to other B-slot options, though her flier status limits her to only a few notables.
  • Guard Bearing halves any incoming first hits in enemy phase, allowing her to bait out larger threats before counterattacking others. However, the fact that it only works once per turn tends to be a turn-off. 
  • Mystic Boost grants a nice amount of healing after every combat, which can be advantageous in more longer-winded phases with multiple fights. It also cancels the "Calculates damage from staff like other weapons" effect of staff users, allowing her to bait the likes of Sara and Brave Veronica more comfortably. 
  • Guard is a non-premium option which delays enemy Specials, an advantage versus enemies with guarunteed follow-ups, but has a rather strict working HP threshold of ≥80% HP.  
• Farina should run a sustain Special above all else, lest she gets worn down quicker to the point of defeat or knocking her out of her Lance's HP condition (≥25% HP). Noontime generally works best as its cooldown gets reduced to 1 thanks to Hotshot Lance's slaying effect and activates on most counterattacks. Sol should be considered if running outsourced Breath support, especially Geirskögul or Renewed Fang.
• There's very little good reason to replace Atk/Def Rein. Not only does it spare inheritance costs by coming by default on Farina, but also ensures all her matchups are softened by applying -4 Atk/Def to the enemy.