The alchemist creates a Diminutive or Tiny tumor on his body, usually on his back or stomach. As a standard action, the alchemist can have the tumor detach itself from his body as a separate creature vaguely resembling a kind of animal suitable for a familiar (bat, cat, and so on) and move about as if it were an independent creature. The tumor can reattach itself to the alchemist as a standard action. The tumor has all the abilities of the animal it resembles (for example, a batlike tumor can fly) and familiar abilities based on the alchemist's caster level (though some familiar abilities may be useless to an alchemist). The tumor acts as the alchemist's familiar whether attached or separated (providing a skill bonus, the Alertness feat, and so on). When attached to the alchemist, the tumor has fast healing 5.
I believe the bolded portion explains that the tumor is, by most regards, just your Familiar. The main difference is that it requires a standard action to separate if you want it to move beyond your square.
Although, honestly, it could use a little more clarification.
This ability makes the tumor familiar a little overpowered when combined with the protector archetype for familiars. It becomes a fast healing hit point battery.
Valet Archetype + Escape Route is fun, too.
A Human Bloodrager (Aberrant Bloodline) could have both at first level.
4) Does an attached tumor familiar need to eat? Or sleep?
This feat:
strongly suggests that the Tumor familiar exists as a separate entity and can take actions.
Nice find.
I had really hoped the Familiar Folio would clear up some of the confusion regarding Tumor Familiars. We get a lot of threads about them.