I'm saying that even if you get the ability to cast divine spells as arcane spells, you don't necessarily have an arcane caster level. That's why Southern Magician doesn't work. You have to have an arcane caster level in order to get the feat, not just be able to have divine spells cast as if they were arcane. Just like you have to have a class for Practiced Spellcaster to function, Magical Training won't do it.
For a concrete example, this is what I meant when I said "using 3 feats on a familiar".
Human Cleric 3
Domain: Community
Human bonus feat: Alternative Source Spell
Level 1 feat: Magical Training
Level 3 feat: Obtain Familiar
Qualification for Obtain Familiar: Community domain spell-like ability is at caster level 3. This qualifies the cleric for Obtain Familiar (so sayeth Complete Arcane, though see the caveat in my previous post about the word "instead").
Familiar advancement: With Alternative Source Spell, a cleric spell from a cleric slot can be cast as an arcane spell. Cleric is therefore a class that "allow you to cast arcane spells" and counts for familiar advancement according to the Obtain Familiar feat. (This bit could probably use some work.)
I'm not seeing where you need an arcane caster level here.
I must be missing your point somehow.