Although I haven't had a chance to truly evaluate my skill at homebrew, I've given translating Spheres a shot, and what I've found is that it basically isn't necessary.
The core reason behind the Spheres systems' existence is allowing greater flexibility in character creation, and KF already has that in not just spades but clubs, diamonds, and hearts as well. Additionally, KF is built on having basically one or two ways to allow your character to do a thing. Adding Spheres wholesale is like adding five more of those ways.
There are a couple things Spheres can do that KF can't. SoP lets you build your own casting system, for example. I think this could be simulated by allowing a character to give up a certain number of spell slots per level in exchange for the same number of levels of metamagic applied to their spells for free. There are also a couple things an SoM character can do that a KF character can't, but those can just be converted into feats.
Prerequisites: BAB +1, Weapon Specialization (a light- or one-handed melee weapon).
Benefit: As long as you are wielding a light or one-handed melee weapon with which you have Weapon Specialization and you aren't wielding or carrying anything in your other hand, you gain a +1 shield bonus to AC. This bonus increases by an additional +1 per 5 points of your base attack bonus above +1 (i.e., +2 at BAB +6, +3 at BAB +11, and +4 at BAB +16). If you cast a spell, make an unarmed strike, or otherwise use your off hand, the benefits of this feat cease until the beginning of your next turn.
* If your BAB is +16 or higher, you may apply your weapon's enhancement bonus to the shield bonus you gain from this feat.
Synergy: If you possess the Somatic Weapon feat, you may cast spells without losing the benefits of this feat.
Source: This feat supersedes the Equipment Sphere talent of the same name, from Spheres of Might.
5-seconds-later edit: Oh yeah, and spell points can basically be done like psionics' power points. I admit I don't know much about that, but one spell point per spell level for each base spell slot, plus your casting ability modifier, sounds about right.