If the seventh seal is synchronous with the seventh trumpet, then the Little Scroll could well be the scroll that the Lamb is opening one seal at a time in Revelations 6:1-8:5.
The Great Multitude in white robes in Revelations 7:9-17 would, therefore, be the rapture of the Church at the Last Trumpet.
Could the Little Scroll be the same as the Book of Life? Once it is opened, those who are saved are resurrected or raptured to be with Christ in the clouds.
The Church is judged separately to the Nations (Pagans/Gentiles).
The Church is called up to be with Christ in the Clouds when the seventh trumpet sounds. They stand before the Judgment Seat of Christ and are judged for the things that they have done in the body of Christ. At the same time, false christians in the Church are sent to hell by the angel in charge of the fire (Revelation Ch 14).
The pagans who have died are not judged until the end of the Millennium at the Great White Throne. Those who are alive when Christ returns will suffer the seven bowls of God’s wrath and will be separated into the Sheep (who were kind to God’s people) and the Goats (who persecuted God’s people). Some of these ‘Sheep Nations’ will be allowed to continue to live on Earth as the Nations during the Millennium.
Some Pagans (Gentile / Nations) escape the Lake of Fire and are allowed to spend Eternity as the New Nations basking in the Light of the New Jerusalem. They are even given the Leaves of the Tree of Life for healing and they are allowed to enter the New Jerusalem once a year. It therefore follows that these nations must not have accepted the mark of the beast as they were not thrown into the Lake of Fire. It also follows that their Names must be in the Lamb’s Book of Life as they are allowed to enter the New Jerusalem once a year. When they are judged at the Great White Throne at the end of the Millennium, if their names are not in the Book of Life they are thrown into the Lake of Fire.
The Book of Life must, therefore, contain the Names of Pagans who were not thrown into the Lake of Fire.
The Book of Life is opened once at the beginning of the Millennium to judge Christians and it is opened again a the end of the Millennium to judge pagans.
The Born Again Believers’ names are listed on the Little Scroll which is part of the Book of Life.
The Names of Pagans who are spared the Lake of Fire are listed on a separate scroll (let’s say it is called the ‘Big Scroll’) which is also part of the Book of Life.
The Little Scroll therefore contains the names of born again believers in the New and Old Covenant times. When it is opened the Believers get resurrected (if sleeping) or raptured (if alive).
The ‘Big Scroll’ contains the names of all Pagans who are spared the Lake of Fire and are destined to be the Nations in Eternity.
Both the ‘Little Scroll’ and the ‘Big Scroll’ are therefore pages or chapters in the Book of Life. They are a subset of the Book of Life.