5.1.3. How do I build the ability to transfer FP from myself to others?
You can come close simply by taking Healing, allowing one of the FP-healing modifiers for Regeneration (Heals FP Only -0% or Heals FP +100%), and simply ruling that the rate is 1:1 because 2:1 would be abusive.
new modifiers in P51
p151 "Healing Drug" and "Universal Antibodies" use Blood Agent
page 47 uses Contact Agent as a modifier on it
Thaumatology - Sorcery page 17
- "Note: The 4 HP of healing has been converted to dice per p. B269."
page 15 of GURPS Powers: Divine Favor has "Lay on Hands (Enhanced)" which has interesting modifiers which are informative in designing abilities.
"Can only spend 5 FP when healing injuries, -5%;" is similar to Capped, but that is normally worth -5% for being limited to 10 FP. This falls in the range of "-20% for 4 FP, -15% for 6 FP," but is like applying the -20% "injuries only" limitation from B59 to the limitation, functioning as a Limited Limitations.
More traditional Limited Enhancements are "Reduced Fatigue Cost 5, Disease Only, +60%" and "Reliable 8, Only to offset disease penalties, +20%". Normally RFC 5 costs +100% and Reliable 8 costs +40%. Applying the -40% "disease only" turns 100 into 60, it should have changed 40 into 24, not 20, so that is possible a typo.
I'd build this as: Healing (Emergencies Only, -30%; Empathic, -50%; Faith Healing, +20%; Injuries Only, -20%; Limited Use, 1/day, -40%; Ranged, +40%; Reflexive, +40%) 
- Healing is an exception -- AFAIK, adding Ranged does turn it into a Healing Ray. This makes sense, since it's not a contested thing, and healing rays have a fair amount of fictional precedent.
- That said, it wouldn't be visible unless you added Visible, so I don't think there's really a big difference between, "I roll IQ to target him, minus range modifiers, but he won't dodge because he wants this. If successful, my ray hits him and he's healed," and, "I roll IQ like a malediction, but he won't resist because he wants this. If successful, my power works and he's healed."
- So calling it a malediction instead of a ray is pretty much a special effect. You lose the ability to aim, but gain the ability to heal through walls and windows and such. Fair trade.
- HEALING RAY: Two rolls. Speed/Range penalties. Can Aim. Can Move and Attack or All-Out Attack. Fixed max range.
- HEALING SPELL: One roll. Range penalties. Can All-Out Concentrate (much worse than All-Out Attack, esp re: movement).
- Otherwise, both are invisible and ignore DR. The ray takes Size modifiers, but that's a good thing as often as a bad thing.
- Hmm. It does seem that the malediction has a small net advantage over the ray. Maybe a custom +20% enhancement (similar in strength to Based On ) would be more fair than making it a +0% special effect?
- Healing has a built-in limitation, that you get a cumulative -3 penalty per successful use that lasts for a day after the last use.
- How do you get rid of it? Cosmic, No cumulative penalty, +50%?
- Yes. By way of comparison, note that this costs the same as Reliable 10, an enhancement which not only removes the penalty, but gives a net bonus for your first three uses -- but then quickly ceases to stop your activation rolls from sliding into Penalty Hell. Using Cosmic instead to remove that one drawback means that you never get a net bonus, but you can heal one person all day long without special penalties.