Arcane spells without levels in spellcaster class?

[LentilNinja]

I'm trying to find ways for classes like Warlock to get into PrCs that say "ability to cast 2 level spells" like Eldritch Knight, Noctumancer or Anima Mage to advance Warlock instead of a caster. While I could just dip into a caster and then take Precocious Apprentice, I want to see if theres any in-game alternatives. So far this has been looking bleak but I have a couple of questions for how to do this:

1. Precocious Apprentice (should it be allowed to qualify for 2nd level spell entry) says "arcane caster level 1st, Spellcasting ability (Int or Cha) 15". Now while I'd say Warlock counts as an "arcane caster", the Spellcasting ability part seems more ambiguous. Charisma doesn't grant him bonus spells or such but does affect the DCs. Thoughts?

2. Sand Shaper gives a bunch of spells to a character. Could they then count as knowing 1st level Arcane spells thus get in? Probably not but thoughts?

3. Any other ways of doing this?