Like split-personality disorder?

When we have not yet determined how it can contain a single consciousness, how can it contain a second

No, like how you say it joins with god

I believe that your soul is your own and it is your soul that gives you will. You don't have direct will over your body or your spirit/subconscious being, but you have the power to shape your body and spirit through your actions in the world.

So I wouldn't call it multi-conscious because they are all codependent on each other to maintain a consciousness.

That would infer that you were incapable of exerting your own will

No, but to exert your will you have to contest both with your body and your subconscious mind.

People do not have free will innately

According to a Christian perspective your will is either a slave to sin or righteousness

My perspective would be that your will is your intent, and your actions are the embodiment of your intent

Gnostics generally deny the idea of objective sin, since a sin is only perceptual.

Therefore your will is free

“I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do.” - Heinlein

Similarly there is no original sin, Humanity was just in eating from the Tree of Knowledge because it granted them consciousness and free will.

Because of that, Jesus Christ (Yeshua Ha'Notzri) was not seen as a figure meant to be the redeemer of Humanity, but as a Buddhic figure brought into the world to share divine insight and enlightenment.

The Christian argument is that it is because of free will that the decision to eat the fruit ocurred, not the result

Well the snake tricked Eve

She ate from the tree because she didn't have free will.

Eden was a false paradise.

Thats not necessarily the case

It was the idyllic bliss of Man living in Nature.

She ate from the tree because she had the free will to decide between the things that God told her and the things the snake told her

What I am saying is pretty subjective

And that is probably the more canonical interpretation

Her intent was to find out the truth, her actions were done under the supposition that the snake was telling the truth

Snake dindu nuffin

She has free will, but decided to act based upon an incorrect supposition

She lacked the knowledge to know that the snake was evil

Another argument would be that the existence of the tree and the snake prove that there was free will, because without the ability to explore those options, your will is not free due to being shackled through limitations

That is a more apt way of putting it

So according to that way of thinking, you do innately have free will

But, if your consciousness is joined by that of an external party, then surely you no longer have free will

Because when your will is no longer your own, it cannot be free

If put into semantics it would be better to say you innately have 1/3 free will.

Your soul is your own, at least a normal persons soul is their own.

You're spirit is aspect of your consciousness that you do not control with free will, your subconscious.

And you're body is innately limiting, because its flesh and material.

To have full free will is to have absolute control over the nature of existence

That is not true

What you will becomes what is

Free will is the ability to manfest your intentions to the world