Those with an inherent connection to magic often attract creatures who feel a similar instinctive pull toward magical forces. At 1st level, a sorcerer, bloodrager, or any other character with one of the following bloodlines can choose to gain a bloodline familiar. The character gains a familiar (as a wizard’s familiar), treating her class level as her wizard level for the purposes of this ability. This familiar has an additional ability listed below based on the master’s bloodline.
This replaces the 1st-level bloodline power granted by the character’s bloodline; in addition, the character gains bonus spells from her bloodline one level later than she normally would.
It modifies bonus spells.
Bonus Spells: A crossblooded sorcerer may select her bonus spells from either of her bloodlines. The sorcerer also has the choice to learn a lower-level bonus spell she did not choose in place of the higher-level bonus spell she would normally gain. Lower-level bonus spells learned this way always use the spell level that they would be if the sorcerer had learned them with the appropriate bonus spell.
It modifies bonus spells.
Archetype Stacking and Altering: What exactly counts as altering a class feature for the purpose of stacking archetypes?
In general, if a class feature grants multiple subfeatures, it’s OK to take two archetypes that only change two separate subfeatures. This includes two bard archetypes that alter or replace different bardic performances (even though bardic performance is technically a single class feature) or two fighter archetypes that replace the weapon training gained at different levels (sometimes referred to as “weapon training I, II, III, or IV”) even though those all fall under the class feature weapon training. However, if something alters the way the parent class feature works, such as a mime archetype that makes all bardic performances completely silent, with only visual components instead of auditory, [n]you can’t take that archetype with an archetype that alters or replaces any of the sub-features[/b]. This even applies for something as small as adding 1 extra round of bardic performance each day, adding an additional bonus feat to the list of bonus feats you can select, or adding an additional class skill to the class. As always, individual GMs should feel free to houserule to allow small overlaps on a case by case basis, but the underlying rule exists due to the unpredictability of combining these changes.
It is unclear if it is an archetype, but it modifies the class feature. After it has been modified, you can't take an archetype that modifies the same class feature as you don't have the standard version.
Bloodline Familiar is not a Sorcerer Archetype.
Point of fact, Bloodline Familiar is not even a Familiar Archetype, as qualified by its blurb (“N/A; not technically an archetype, affects the familiar’s owner”). What you couldn’t do is have your Sorcerer take a Bloodline Familiar AND Blood Havoc.
This combination simply ensures your Sorcerer will get most of their bonus spells later than is optimal for one or more of them… and that you won’t get your bonus 9th level spell unless your party runs some flavor of epic/post-20th level game.