God has free will. We have been made in the image of God. Thus, we have free will. (Obviously, this does not directly address the arguments against this position.) There is absolutely no reason to think that we will no longer have free will, in the next life.
Free will implies the (theoretical) possibility of evil. As "Steven" says (approximately), it is strongly true that God will never sin, because He is holy — not just good, but positively and powerfully opposed to evil. Conversely — having free will — it is theoretically possible for Him to do evil. (If it were not theoretically possible for Him to do evil, then there would be little kudos or glory in Him so not doing. (A robot that never does evil is not morally good, on account of being a (deterministic) machine.) )
As “Fofole” notes, in the question, “The Bible tells us that there will be no sin in Heaven.”
It follows that the reason for this (absence of evil) is for some reason other than that it is not theoretically possible.
My view (behind which there is a lot of thinking) is as follows.
The fact of evil arising — noting that this took place in Heaven (apart from the connotation that this denotes the next life) — was strongly anomalous — for some of the reasons that it would be anomalous in “Heaven” [here meaning the next life]. That is… evil is bad — it has bad effects (by definition) — and this would be strongly apparent (before the deed) in Heaven. Thus, the idea of doing evil, in Heaven, would have negative appeal. [Actually, that is a simplification (possibly an oversimplification).] [Of course, conversely, one must have some account of why then Satan would do this.]
Under my view, this would have even greater negative appeal in Heaven in the next life, on account of the lesson of seeing evil in action on Earth — to the point that nothing else would be needed, practically. (One element of this is the [then now] clear historical event and illustration that there is a Fall involved — that the possibility does not exist, of simply doing one evil act.)
Over and above that, though, (under my view) anyone who attempted to sin in “Heaven” — here meaning the next life — would be instantly cast into Hell.