Who or what was Huan?

[Curufin]

Can't answer that, I'm afraid.

Does a Maia have a fëa? Does a Vala have a fëa?

I don't know.

[Elennár]

Originally Posted by Curufin

Can't answer that, I'm afraid.

Does a Maia have a fëa? Does a Vala have a fëa?

I don't know.

No, they don't. There is a fundamental difference between a fëa of a Child of Illuvatar, and an Ainu: a fëa is incomplete without the hroa, it needs the body to survive/reach its full potential.
Whereas an Ainu doesn't require physical bodies to survive at all, they're just used as a matter of convenience/choice/taste.
Ulmo, for example, didn't like taking physical shape that much; so he didn't unless he absolutely needed to.
This is turning into a rather Off Topic rant, but I think that a physical body limited the power of an Ainu in some way- almost the opposite of an Incarnate, such as an elf or human.
So, if Huan was an Ainu, he would've been unfallen (being in the service of Manwë). That would mean he would've been able to forsake physical shape.
But he didn't.