QuoteSol Blade: 180 Atk, Pure Earth
Herculean Axe: 193 Atk, -10 Def
These are effectively the same weapon. Neither the damage nor the defense will make an especially big difference on the axe, such that the player will barely notice it. If the player is using an unleash setup, it's purely about whichever has the bigger unleash. Otherwise, if the player is predominately casting Call Dullahan (or similar), they're the same weapon.
QuoteLachesis Rule: 147 Atk, 118 Int, 25 Power
This is the default choice for any caster. No other item you listed comes even close to competing with it. Highest Int *and* the highest EPow rating makes it a no-brainer, regardless of whether your role is damage or healing. For a caster item, it also delivers pretty respectable Atk.
QuoteTisiphone Edge: 163 Atk, 48 Int, 8 Def, 4 Agi
Vajra Mace: 171 Atk, 20 HP, 26 Int, 15 Power, 10 Resist
Most of the extra stats on these items are irrelevant. The Vajra Mace is able to compete with Sol Blade or Herculean Axe, since it's a minimal loss of Atk but gives EPow. Tisiphone Edge is only relevant to Ivan (if you want to spec him as a physical attacker, since he can't equip anything better here); it could be relevant to more characters if the Agi is relevant, but I don't know how you're planning to scale Agility in this hack, so I'm not sure if 4 is a lot or a little.
QuoteClotho's Distaff: 139 Atk, 97 Int, 12 PP, 25 Resist
This item doesn't exist. It's completely outclassed by every other weapon listed. Unless you're going the disgaea route and making healing based on res, this item offers nothing to anyone.
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Functionally, you only have two weapons here, possibly three: A caster item in Lachesis' Rule, a melee weapon in Sol Blade/Herculean Axe/Vajra Mace, and possibly an agility-boosting weapon in the Tisiphone Edge. That's *if* the agility is a meaningful amount, otherwise it's just another melee weapon that you only pick because it's all you have left.
Based on your rationale for the items, this is how I'd fix it:
Sol Blade:
-- This will act as our baseline. Since I didn't like the way the ratios were working out with some of the other items (especially the axe), I opted to raise its Atk slightly.
Herculean Axe:
-- This is by far the greatest physical damage weapon, but you should feel that defense drop. Axes should cause you to lose almost a full piece of armor, but grant that same amount as additional Atk over a Long Sword.
Lachesis' Rule: 147 Atk, 118 Int, 25 Power
-- Untouched, since other items got more powerful around it. This remains the go-to item for a pure caster. Note that the EPow on this weapon boosts its damage further, while also improving healing.
Tisiphone Edge:
-- Cutting out the pointless defense, and raising its Atk to make it a better contender as a physical option for mages. More agility to make the stat meaningful.
Clotho's Distaff: 139 Atk,
-- Yes, you read that right. That says 12 to *120* PP. With the incredibly low offensive stats on this item, it needs to provide hella fuel.
Vajra Mace: 171 Atk,
-- Cutting the pow/res since it didn't do much to create an identity for the item. Provides slightly weaker offense than a light blade and doesn't give agility, but makes up for it with some hefty bulk. I picked 108 for thematic reasons, but it comes out to be about right for an endgame weapon like this.
* (The agility on Tisiphone Edge assumes an average party agility of around 80-100 at endgame. If you're using a higher or lower average agility for characters, it should be set proportionately.)
The point of these modifications was to sharpen the identities of the items. Light Blade damage was brought up to be on par with Maces, since both weapon types serve the purpose of helping a caster spec into physical damage, but only Mia/Sheba can use maces, while only Jenna/Ivan can use light blades. Lachesis' Rule is untouched since the power of other items went up around it; if I had instead opted to leave Sol Blade alone and nerf the damage on Maces down to the level of Light Blades, it probably would've lost somewhere around 10-15 Atk. Despite the pretty massive stat buffs to Agility or HP on LBs/Maces, the Sol Blade should still be plenty attractive to primarily physical damage dealers, provided that Long Swords get generally stronger unleashes.
Don't be afraid to give items a unique niche. If you water down their stats too much, they just become more of the same, and you still just end up choosing whatever gives the best damage.
edit: Also, I think it's a mistake to add the "has innate attack attribute" to all weapons of a specific weapon type (e.g. making all Long Swords have an innate elemental attribute on attack, like you do here). That's predominately used to add flavor to certain weapons, and you miss out on the opportunity to do some really cool stuff with other weapon types. Of note, it barely even factors into the power of a weapon at endgame, since if you're using the Attack command, you're probably going for an unleash anyway; it can factor into the power of weapons earlier in the game (when you don't have a very high crit chance yet), but that can easily be accounted for by just knocking a couple points off Atk, if you even choose to do that much.