At a previous museum, we had a large collection of scrapbooks with a tremendous amount of historical value that had not been properly cared for and had serious vinegar syndrome issues. They were deteriorating to the point that we HAD to disassemble them. However, before taking them apart, we copied each page the best we could and placed the copies in a three ring binder in the same order they were in the scrapbook in order to preserve the historical integrity of the collection. That way, if anyone ever wanted to go back and see exactly how the items were assembled in the scrapbook they could. This is the best solution I’ve found to preserving scrapbook collections that won’t last long if they stay in their current, original housing.
I’ll let someone else better aquainted with archival preservation address your question of how to remove the photos from the scrapbook itself.