I am building a fate core petty dabbler in the arcane, and I am trying to build an alchemy stunt relating to turning lead into gold (lore skill instead of resources) what do people think is a good limitation for such a skill?

Arlen aka the painted man is a guy who fights demons he is covers in wards that steel demons powers and utilise it against them. He probably has pretty much supernatural everything, a vampire power that only works vs demons, the ability to become incorporeal, fly and teleport. He fits in to the broody saviour archetype.

Ps the painted man books are well worth a read imo

Yes accuracy 9 and weapon 13 over 4 zones good but at 17 refresh a caster could easily be attacking for accuracy 16+ (+4 specialization, +6 skill + 6 focus) with high weapons rating, a crafter could be boosting himself with 4 aspects a turn (love the thaumaturgy) and defending, attacking, veiling and blocking at 12.

I don't feel my character has been massively effective with them. The 10 refresh wizard I am playing Manema probably could have ended our current fight already.

For the Darkness

True Glamour, PI with a catch of daylight, mythic everything, breath weapon, incite emotion fear (all upgrades) plus a basic fantastic at weapons, fists, ranged, deceit, athletics and intimidation.

The minion creation is unstattable as is the territory creation. Generally look at them as true seemings with an absurdly permissive gm.

Haven't read the witch blade series.

I was thinking the damage aura power and how it might be upgraded to represent a powerful illusionist ability to get his enemies to kill each other whilst they are supposedly shooting at him.

Re-Direct (-1)
When someone misses you with an attack which would usually cause them to take stress from damage aura you can choose to instead target another enemy who they could have hit (same zone for melee, two to three zones away for ranged) using your defence roll as an attack roll.

Well back when it was 3 refresh I thought teleport should just allow you to ignore grapple but I suppose for 1 more refresh than flying ignoring grapples is a bit too much.

As for carrying other people I always thought it should be limited by how many people you could physically carry (might/strength powers). 

Also we should have included some proviso that the movement ends early if you attempt to teleport into something solid.

As for using the ability as a weapon I always assumed the only way to do it was via grappling an opponent, moving them, then dropping them from above which you can already do with wings (the should get a might roll to hang on). So I didn't see much of a problem.

So the choice of when the stress will come into effect is made when the attack hits?

Yes