So bloodline familiars are options given to classes with bloodlines to gain a familiar.
They are not stated to be Archtypes. In someways they act like Archtypes, in someways they don't. They modify class abilities but they work on many classes.
My question is, Is taking a bloodline familiar considered taking an Archtype?
This matters because it effects stacking with Archtypes, particularly those that change what bonus spells are gained at a level. If this is not an Archtype (it is never called one) then it can be stacked with these Archtypes pretty simply. If it is an Archtype (it behaves similarly in some ways) then it can not be stacked with these Archtypes.
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. For example, a sorcerer with the aberrant bloodline who takes a bloodline familiar would not gain the acidic ray bloodline power, and she would gain her first bonus spell at 4th level, her second bonus spell at 6th level, and so on.
Wait...question...do you mean an archetype for the caster, or for the familiar?
Anyway, for the caster- I would say it is a very small archetype that only concerns that one power that is traded out. Because if you had an archetype that traded out the 1st level blood rager power, and that was already being used for familiar...well then you either don't have the bloodline power to trade for the archetype, or the ability to get that familiar was traded away for the archetype.
If it is for familiar- probably not. Most of the costs appear to be from the caster.
Whether or not it is, and I think it is, it would prevent you from taking an Archetype that modifies the 1st level bloodline power and bonus spells (delaying them).
If it is an archtype, then you are correct for sure.
If it is not an archtype and you wish to take an archtype that only switches out a couple bloodline spells, then it is not as clear. The prohibition on changing the same thing twice is a prohibition on two archtypes changing the same thing twice.
A character can take more than one archetype and garner additional alternate class features, but none of the alternate class features can replace or alter the same class feature from the base class as the other alternate feature.