jlags,
Must say that scrapbook sounds like a really wonderful record of your relationship.
Regarding using it as part of your application submission, personally I don't think it is needed, unless you feel that proving a genuine relationship may be a weakness for you.
Of course, it won't do any harm if you do include it, but remember that the ECO will have seen 100's of applications and is experienced enough to know just what key issues satisfy the requirements or not.
Although there is no requirement that two people must spend a specific amount of time together in person, it is reasonable to expect that the ECO may be skeptical of couples with only a very minimal face-to-face history prior to application.
Hopefully you can get the balance right.
Get your fiance to write a really good letter supporting your application, and outlining how long you have been together and important events and meetings between yourselves.
You may also briefly outline the start of the relationship, how it developed, the times you met face-to-face, some things you did together, your feelings for each other, why you want to marry, plans for the future and where you will live and how you will support yourselves.
If there is anything complicated or unusual about your application this letter is where you should include a clarification for the ECO.
You could strengthen the application by including a supporting letter from your fiance's parents saying that they support the future marriage and that they are looking forward to meeting and welcoming you into the family. Nothing complicated, keep it simple.
Just my opinion. Others may see it completely differently.