Can I use Poly Self on a Homonculous Familiar?

[Cyclops]

One one hand it is a construct. On the other, any spell with a target of YOU can be cast on a familiar.

 

[Aziraphale]

One one hand it is a construct. On the other, any spell with a target of YOU can be cast on a familiar.

The PHB states that the familiar becomes a Magical Beast instead of its previous creature type, but I'm not sure whether that applies to the Homonculus - they're not standard familiars, after all.