Falgoon |
Spell focus is not a metamagic feat. This feat doesn't double metamagic values, it doubles the static effects that other feats apply to your spells.
Spell focus for example gives +1 bonus to a given spell school. The effect is set (static), it's not a metamagic feat, you can never cast from this school without it, thus it's effect is doubled.
You choose if or if not to apply a metamagic feat to something, so it wouldn't be considered a set numerical bonus, because it's not set.
The feat only says it effects feats, so Eldritch Heritage, traits and such shouldn't apply.
You do however still get the free metamagic feat.
As a side note, It's impossible to double quicken anything, since you can only make one swift action per round.
There are some fun tricks with this feat however.
Greater Spell focus can be combined with Greater Elemental Focus for a total of +8 to the spell DC. You can even use "Elemental Spell" as your free metamagic feat and make your Finger of Death super evil.
This feat, alongside, Spell Specialization, Varisian Tattoo, and Bloatmage Initiate can raise your caster level in necromancy to +8. Then with the spells Deathwine, Death knell, and the Drug Aether you can actually have a caster level of at least +13!