Best Race / Bloodline / Spells for Ancestor Eidolon?

[deuxhero]

Relevant abilities (From Blood of the Beast)
At 1st level an Ancestor subtype Eidolon gains the racial traits (no alternate traits) from the Summoner's race (not sure if this includes ability adjustments).

A 4th level it gains the sorcerer, fighter or rogue simple class template as though it had 1 HD (but can't have abilities a level 1 member of that class wouldn't)

At 12th level those advance to be as if they had 5 HD.

Biped only naturally makes the ancestor favor weapon wielding builds. For this I think the best race is one with proficiencies or Human (who can blow the bonus feat). If Half-Elf (and their ability to pick human stuff, elf stuff and half-elf stuff) lets you pick one of the three, they are likely the best.

Spells will only be level 1/2 and an Eidolon is (sorta) full BAB so it would seem like typical Gish pick, but the obvious ones can be cast on the Eidolon either directly (Mage Armor) or via Share Spells (Shield) so the longer duration ones seem like they should be skipped. Thunderstomp seems an option, as you can still use Strength and BAB if you want to, as does Longarm (Being huge means huge reach. Being huge and having Long Arm means huger reach). Prehaps Extra Traits (Magical Knack/???) and Pearls of Power would be worth it for them?

Bloodline though I have no idea what to pick. Most Sorcerer Bloodlines don't have good 1st or 3rd level abilities for a gish.

[deuxhero]

The alternative to sorcerer is growing stupidly strong (being +6 ahead of other Eidolon) with fighter, but there's really no question on optimizing that.

An alternative to biped is racial and/or bloodline given natural attacks, but I have no idea how to optimize that.

[avr]

Ghoul Sorcerer bloodline gets to paralyze people with its claws at 5th level, using the 1st level power. The bloodline arcana would be pretty pointless though, it's not going to be casting offensive spells. Nanite bloodline might be better for that with the duration increase to some personal spells, thinking about it, though the poison is less impressive than ghoul paralyzation.

With Fate's Favored the Destiny Bloodline might be worthwhile as a Gish.

[deuxhero]

Ghoul Sorcerer seems interesting. The third level ability for +1 and cold resist 5 isn't bad either. That will only come online at 12th level though.

Fate's Favored will require the Additional Traits feat, but there are plenty of options for the second (like Magical Knack or one of the many initiative/save/whatever boosters or the handful of traits that grant proficiency)

[Pounce]

Ratfolk summoner? Abuse swarming like nothing else!

[The Sideromancer]

Can you use Racial Heritage shenanigans? that might be fun.