You need basic bloodline potency before you can take advanced bloodline potency. You should probably use it to pick up Cantrip Expansion since you aren't bothering with spell slots.
That looks right. Also no you don't get the bloodline magic unfortunately. The dedication is pretty clear about what it gives you and then says that you don't get anything else so if it isn't in the dedication description you don't get it.
Actually its not quite right. You can take the initial bloodline power at 4 through archetypes, but you only get the second and third bloodline powers at 6 and 10 if you're a sorcerer. If you were multiclassing sorcerer you'd only be able to get them through the feat that lets you take sorc feats at half level, meaning you'd get the second bloodline power at 12 and the final power at 20.
Ah! Good catch.