Sorcerer bloodline powers, spells and feats are only gained by leveling in sorcerer. With the exception of dragon disciple, prestige classes that advance spellcasting levels do not advance bloodline.
If you want a familiar as a sorcerer, see the arcane bloodline.
Agreed - Familiars are part of the "Arcane Bond" class feature of Wizards, and Sorcerers of the Arcane bloodline get Arcane Bond (and thus can have a familiar or bonded item).
And no, bloodline powers do not progress unless it explicitly says so. The "enhancers" of Pathfinder are primarily to the core classes. The extras they get generally do not get passed on to prestige classes for free.
If you can use 3.5 material, the Obtain Familiar feat from Complete Arcane should allow a PF arcane caster that has not an arcane bond to obtain a familiar. This includes bards, sorcerers and eldritch knights.
I wonder how much it would be worth as a feat, similar to Practised Spellcaster.
Potent Bloodline
Prerequisites: Sorcerer level 1, Spellcraft 5
Benefit: Your sorcerer level is counted as up to four levels higher, to a maximum of your Hit Dice, when determining bloodline bonus spells and powers.
I would never allow such a feat. If you want the powers of your class you stay in it.
I would never allow such a feat. If you want the powers of your class you stay in it.
Don't look in seeker of secrets then... Boon companion does just that for familiars, animal companions and the like.
I would be likely not to allow it as well. Have to see it first.
Those feats seem generally reasonable to me.