The record in Genesis deals with God's creation of our physical world (universe) culminating with the crown jewel - humans (created in the image of God). It does not specify that He created the angels during this time. Perhaps He had created the angels much before (and heaven as well). Was there the passage of time before God created it in Gen1:2?
The fact that Revelation states that stars were cast down I don't believe refers to our physical stars that were created on day 4 but rather that they are heavenly beings. Much like the dragon in that same passage is not a physical dragon but Satan himself "who masquerades as an angel of light". In Isaiah, there is a reference to the morning star and how he said in his heart I will ascend to heaven, I will raise my throne above the stars of God (Isa 14:12). This is in reference to Satan pridefully boasting to be more important than the other angels and so much so that he will be "like God". These star references are not our physical stars but angelic, heavenly beings. There is a lot of metaphorical, pictorial depiction in Revelation and I get confused as to when it is literal and when it is metaphorical. This is one of the passages I really don't think refers to literal stars.
If the above is true, then there is no problem in maintaining the integrity of a 6 day creation and the concept of sin/death being introduced through Adam and subsequently to us, his seed.
I agree, it is not literal stars falling. As for when it is literal and when it is metaphorical, I always look for both. Proceed with caution here, a wrong turn can lead to a cult.
Back to Genesis. I personally don't think that Satan was created before the beginning (Genesis 1:1). If there is a gap in the six literal days, the obvious place would be Genesis 1:2. Thus when God said let there be light, We see resurrection. This is an interesting way to start the scripture, a metaphor, birth, death, and resurrection.
If this is true then we can confirm it and it gives us a gap an Genesis 1:2. You know the author. Is this the sort of thing you would expect God to do? If so, then you won't be surprised to see this structure elsewhere, throughout scripture.