Leaving your feat partially undefined with "(from 1 to 3, depending on GM's choice)" would lead to discomfort for both player and GM. Pick a number. Failed Student has a tougher prerequisite than Arcane Talent, so it should be stronger than Arcane Talent. On the other hand, it would be strange for it to grant more cantrips than Extra Cantrips or Orisons, so you should limit it to two cantrips at most.
Another big question is if a class, such as Alchemist, Bloodrager, Paladin, or Ranger does not have any 0-level spells in their spell list, then from which list is the 0-level spells selected? I created a Bloodrager archetype that gave it cantrips, and since bloodrager is a barbarian/sorcerer hybrid, I used the sorcerer/wizard list. Yet the Bloodrager playtest had been with magus spells, so perhaps the magus list would have been more appropriate.
If the class is an archetype that loses cantrips from a class that ordinary has cantrips, do the cantrips come from the original list?
You were inducted into a Magical Academy, Tradition, or Apprenticeship at a young age, but turned out to have little talent for the rote lessons and memorization. You did manage to remember a few of the simpler tricks though.
Caster Level of 1+, Does not normally have access to level-0 spells
When you select this feat, choose Arcane or Divine.
For Arcane, spells are drawn from Wizard/Sorcerer Spell lists.
For Divine, Spells are drawn from Cleric/Druid Spell lists
Select 2 Cantrips or Orisons (level-0 spells), you may cast these spells using your Caster Class's mechanics. (For Instance, a Warlock would cast them as Invocations, using his Charisma score as his casting ability score.) This Feat can only be taken once.