Rule Breaker:
I believe Rule Breaker might be somewhat overloaded on the special effects enhancements. As a weapon, it's supposed to be sub par, but with three major qualities.
You got, I think, half of the first one. The ability to cut enchantments properly speaking does not actually sever spells, it steals control of them on a touch, allowing them to be transferred to another subject, or to be discarded entirely.
So the full version would simply dispel whatever spell effect it strikes, and transfers control of the effect to the wielder. To do this, mechanically is just a touch attack against the effect(or summoned/called creature) or it's controller, upon which you roll a dispel, and a successful dispel gives you control, if it can be controlled.
The second part is that it ignores all defenses stemming from enchantments. Rule Breaker strieks as if all your magical AC sources and miss chances are nonfunctional unless they resist a dispel check.
The third is less quantifiable, since it's simply the "ability to break contracts, oaths and bonds", which in a loose sense means all the stuff Break Enchantment can do, and also cutting you loose, scot free from more mundane contracts and promises. What it needs to hit to do this is somewhat unclear though.
All told, Rule Breaker is about Medea comitting all the betrayals, and getting away clean with it in the end, though it never brought her any joy. Apollo comes down to take his grand-daughter off to Olympus in a golden chariot, and her home city made her a demigod.
Gae Bolg:
The rage aspect is a reasonable extrapolation, though not one supported by either legend or Nasu.
Heartseeking Strike is true to source enough, though it's supposed a Reflex save or die, with no attack roll involved. I can see why do it your way though. It's also supposed to be one of the cheapest Noble Phantasms to activate repeatedly
The vampiric effects of Gae Bolg is somewhat unwarranted as well, the mythic weapon is hungry, but it gives nothing to the wielder, while it's thrown aspect is missed. Nasu's Gae Bolg can be thrown to produce an Anti Army effect and unleash it's full power, which successfully penetrated all but one layer of Rho Aius. As a thrown weapon, legendarily it cannot miss, and explodes into thorns on impact.
Overall not a bad take on something that embodies the Hero of Ulster.
No comment on God Hand since it'd be a tough case to translate in any case. D&D doesn't handle that sort of invulnerability well. But you can kill Berserker more than once in a single attack, if it was powerful enough.
Mono-hoshi-zao: Pretty well done. Usage frequency is rather low though. Assassin practically spams the thing, since it costs no prana at all. It's pure skill.
Invisible Air: Pretty good as well, I think the sonic damage adder should be an easier fraction to apply. Not very convenient to quarter, or worse, apply two thirds to, damage and then add it right back.
Knight of Honor: Excellent. Minor quibble in that Arondight isn't transformed from the other weapons, but summoned from thin air. Small difference either way.
Gordius Wheel: Nice bulls.
Prelati's Spellbook: I think it's supposed to produce pseudonatural creautres, but this works just fine. Nothing for the greater summons? I believe the Thing From The Sea is supposed to be ridiculously tough, regenerate at a similarly absurd rate, and so large that it counts as a structure. That and it draws prana from what it eats, so the summoning is self sustaining as long as it has food.
First Folio: Not familiar enough with the Servant to say much about this one. No easy way to implement a reality warping book though.
For Another's Glory: Nothing on the ability to steal a creature's appearance?
Overall: Pretty cool, though these seem to be of pretty wildly variant power levels.