It's my understanding that the slider chests had nothing to do with the roof damage- they replaced some of the original Skinner chests that were beginning to have issues for other reasons. I believe these chest replacements were in the former Positif, which Adams completely re-configured, with the unenclosed section becoming the Vorwerk in a more baroque style (which would fit with the slider chest decision), and the enclosed section immediately behind it becoming unenclosed. It's my understanding that the Adams Vorwerk is the division that is now silent. My visit would seem to corroborate this- the larger Positif seemed to be working from what I could tell of the registrations being used.
The Dodge organ is actually the current one-manual continuo. As far as I know, the Aeolian-Skinner gallery division was still functional at the time of the other Adams work. The 1969 Adams gallery organ was built from this division and other reused pipework, and seemed to be another step in William Self and Adam's fixation with turning any organ they encountered into an early 19th-Century French instrument. This of course was replaced by the current Taylor & Boody organ in the gallery.