Syndactyly
How can someone be perfect in physical form, but no longer have the desires of the flesh? How can they be alive, but after they're dead? How can they be resurrected back into a physical form, completely restored, but have no physical desires? What is the point in keeping human souls separate if by the end of it all they will all be exactly the same?
Interesting questions.
1) Do you remember that Adam and Eve's original bodies did not age? They also knew no pain, and before they decided to sin, had no uncontrollable natural compulsion to. This is kinda similar to the body, the "perfect" one we will get after the rapture, tribulation, and Lucifer's defeat.
The desires of the flesh are to sin, but these desires were put there, not by God himself, but by Adam and Eve when they chose a life of sin and disobedience.
2) Your old body, the one that's a inheritance from Adam and Eve, is dead, but your spirit "lives" on after death. It is this that is given the new "perfect" body. So they are no longer dead, but made new again, which is similar to another verse which says we are made whole, new, and living through Christ.
3) You are assuming this is the same body they had before death. It isn't. It's a new one, one that is void of sinful nature, and devoid of physical needs, such as for food. Is such a thing impossible for The Almighty?
4) I'm not exactly sure what you mean here. The souls that go to heaven before those of the living that live through the tribulation, are separate from earth. But other than that those souls who followed Satan are cast into the fire lake with him at the end of days, to suffer for all eternity from pain and forever separation from God, light, his love, and all the goodness in the world.