We could have been created for all you say in Heaven,
I don't see it that way. Just because Adam was created with a superiority over all creation does not mean that Adam was sin free. We know he wasn't because after all...he fell into sin. So God would have had to have created him differently than He did, in order for Adam to be suited to come into God's presence in Heaven.
Secondly, we understand by the Word of God that God intends for there to be a New heavens (universe) and Earth which man will dwell on eternally. He is still going to accomplish the very thing you think He should have in the beginning, and this new heavens and Earth will be outside the Realm of God, though it will be bridged by New Jerusalem.
That was His intention from the beginning and that is what He will accomplish ultimately. And just as we are stronger through our experiences in life, even so I think our going through what we go through in this life makes for a stronger bond between God and ourselves. Had God just created us sin free we would not have the gratitude we now have through the Redemption which is through Christ Jesus.
There is free will in Heaven or the angles could not have sinned.
The one thing I would tell you about Free Will that I believe every Christian should understand is this: Free Will has absolutely no bearing on Salvation.
The only free will men will exercise in a salvific context is to reject God, and that is because their nature has a proclivity for sin.
Secondly, oftentimes sin is not a matter of "free will," it is a matter of...
...there is no other option left to the individual. "I just had to do it!" is the theme song of the Natural Man.
So in regards to Satan, he just had to do it, because he is, after all, a created being and not perfect in righteousness and holiness as God is. God cannot sin, all others will, though.
This pup could have been in Heaven, why the separation?
It didn't start out as separation, though. The relationship with God was for Adam a face to face communion. He had that as long as he came under obedience to the will of God as expressed to him by God.
I will say this, though, I have often speculated that Adam, knowing his wife's fate for her sin (death), chose to share her fate. He was, after all, the most remarkable man ever to come into existence, second only to Christ the Son of God. Everything in the original creation was better than that which we see now, because everything has been under a curse of degradation since the Fall. Love, in my view, was something better understood by Adam than any other being that has lived since the Fall, so I speculate (and that is all it is) we just might find a nobility (from a human perspective) in Adam's sin someday. Doesn't make his sin against God okay, but, from a human perspective we might understand the love we have for our spouses, and a willingness to die with them should they come under penalty for death. It may be that is why God allowed for the deaths of an animal, or animals, to cover their sin, rather than exacting the penalty upon them physically that say. They did die, spiritually, when the relationship with God ended and they were thrust out of His presence. Again, just speculation.
God bless.