First, let’s acknowledge that your question is generalizable to the entire human race, not just Adam and Eve,
Secondly, it is useful to explain that people in heaven, if they really have free will, could certainly sin. They cannot, however, because there are no sins available to commit.
Everyone in heaven can have whatever he wants, which eliminates a lot of stealing and looting like in New Orleans and Washington, D.C.
There’s no need for reproduction in heaven, so there are no sexual mechanisms, and no built-in instincts and annoying hormones to make it fun enough for humans to want to do it despite the disadvantage of offspring. That eliminates all sins of lust and carnal desire automatically.
Since there is no need to impress members of the opposite sex so as to get laid, there is no lying in heaven. Likewise, since there is no need for things, there is no need to lie about whose harp you stole, since all harps are the same and there is an infinite supply of them.
No one needs houses, cars, food or money in heaven, so no one needs to work. Sins like sloth are irrelevant.
With nothing to steal, politicians will be irrelevant in heaven. Their absence eliminates at least 80% of the lying.
Everyone getting into heaven will be made instantly as smart and knowing as God, and since everyone is beautiful and wears the same brand of glowing toga, there will be no need for upmanship or envy.
There’s no point throwing a punch at someone in an enhanced spirit-body that doesn’t bleed, bruise, or feel physical pain.
The fact that everyone in heaven is already dead pretty much eliminates the need for killing.
Every day is a Sabbath, but there are no asses to haul out of non-existent pits.
There are no other gods in heaven, so who would worship them? God’s name won’t be taken in vain when He is the Big Guy right there in your face, listening, taking the daily roll call of everyone sitting happily at His right hand, strumming away for lack of anything they need to do. It’ll be hard to curse a God who’s given you everything you want. Lots of sins eliminated, right there.
Ultimately there is no sin in heaven because the place is a perfect communist fantasy-land, except without meat-market or bread lines to stand in and sneak to the head of, with nothing either useful or malicious to do. Earth is full of sin because it is a place where there is work to be done, food to be grown, money to be made, sex to be had, children to be raised, infidels to be blown up, and wars to be fought over women, territory, or God— whichever excuse fits best. On earth, thoughts and actions count. In heaven, they are irrelevant.
(This material is copied or paraphrased, with permission, from my website.)